diff --git a/lean_client/Cargo.lock b/lean_client/Cargo.lock
index c0de67c1..4b48388c 100644
--- a/lean_client/Cargo.lock
+++ b/lean_client/Cargo.lock
@@ -149,7 +149,7 @@ version = "1.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "40c48f72fd53cd289104fc64099abca73db4166ad86ea0b4341abe65af83dadc"
 dependencies = [
- "windows-sys 0.61.2",
+ "windows-sys 0.60.2",
 ]
 
 [[package]]
@@ -160,7 +160,7 @@ checksum = "291e6a250ff86cd4a820112fb8898808a366d8f9f58ce16d1f538353ad55747d"
 dependencies = [
  "anstyle",
  "once_cell_polyfill",
- "windows-sys 0.61.2",
+ "windows-sys 0.60.2",
 ]
 
 [[package]]
@@ -602,7 +602,7 @@ dependencies = [
 [[package]]
 name = "backend"
 version = "0.1.0"
-source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=2eb4b9d983171139af36749f127dd9890c9109e6#2eb4b9d983171139af36749f127dd9890c9109e6"
+source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa#5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa"
 dependencies = [
  "mt-air",
  "mt-fiat-shamir",
@@ -1724,7 +1724,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "39cab71617ae0d63f51a36d69f866391735b51691dbda63cf6f96d042b63efeb"
 dependencies = [
  "libc",
- "windows-sys 0.61.2",
+ "windows-sys 0.60.2",
 ]
 
 [[package]]
@@ -2997,7 +2997,7 @@ dependencies = [
 [[package]]
 name = "lean_compiler"
 version = "0.1.0"
-source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=2eb4b9d983171139af36749f127dd9890c9109e6#2eb4b9d983171139af36749f127dd9890c9109e6"
+source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa#5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa"
 dependencies = [
  "backend",
  "lean_vm",
@@ -3012,7 +3012,7 @@ dependencies = [
 [[package]]
 name = "lean_prover"
 version = "0.1.0"
-source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=2eb4b9d983171139af36749f127dd9890c9109e6#2eb4b9d983171139af36749f127dd9890c9109e6"
+source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa#5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa"
 dependencies = [
  "backend",
  "itertools 0.14.0",
@@ -3029,7 +3029,7 @@ dependencies = [
 [[package]]
 name = "lean_vm"
 version = "0.1.0"
-source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=2eb4b9d983171139af36749f127dd9890c9109e6#2eb4b9d983171139af36749f127dd9890c9109e6"
+source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa#5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa"
 dependencies = [
  "backend",
  "itertools 0.14.0",
@@ -3045,7 +3045,7 @@ dependencies = [
 [[package]]
 name = "leansig"
 version = "0.1.0"
-source = "git+https://github.com/leanEthereum/leanSig?branch=devnet4#5cc7e37480362f94e86695428a9ceb9a96b66b97"
+source = "git+https://github.com/leanEthereum/leanSig#c08a3bae74b0d85379cab72dcbefa4091546ecbb"
 dependencies = [
  "dashmap",
  "ethereum_ssz",
@@ -3085,7 +3085,7 @@ dependencies = [
 [[package]]
 name = "leansig_wrapper"
 version = "0.1.0"
-source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=2eb4b9d983171139af36749f127dd9890c9109e6#2eb4b9d983171139af36749f127dd9890c9109e6"
+source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa#5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa"
 dependencies = [
  "backend",
  "ethereum_ssz",
@@ -3701,7 +3701,7 @@ checksum = "1fafa6961cabd9c63bcd77a45d7e3b7f3b552b70417831fb0f56db717e72407e"
 [[package]]
 name = "mt-air"
 version = "0.1.0"
-source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=2eb4b9d983171139af36749f127dd9890c9109e6#2eb4b9d983171139af36749f127dd9890c9109e6"
+source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa#5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa"
 dependencies = [
  "mt-field",
  "mt-poly",
@@ -3710,7 +3710,7 @@ dependencies = [
 [[package]]
 name = "mt-fiat-shamir"
 version = "0.1.0"
-source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=2eb4b9d983171139af36749f127dd9890c9109e6#2eb4b9d983171139af36749f127dd9890c9109e6"
+source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa#5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa"
 dependencies = [
  "mt-field",
  "mt-koala-bear",
@@ -3723,7 +3723,7 @@ dependencies = [
 [[package]]
 name = "mt-field"
 version = "0.1.0"
-source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=2eb4b9d983171139af36749f127dd9890c9109e6#2eb4b9d983171139af36749f127dd9890c9109e6"
+source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa#5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa"
 dependencies = [
  "itertools 0.14.0",
  "mt-utils",
@@ -3738,7 +3738,7 @@ dependencies = [
 [[package]]
 name = "mt-koala-bear"
 version = "0.1.0"
-source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=2eb4b9d983171139af36749f127dd9890c9109e6#2eb4b9d983171139af36749f127dd9890c9109e6"
+source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa#5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa"
 dependencies = [
  "itertools 0.14.0",
  "mt-field",
@@ -3754,7 +3754,7 @@ dependencies = [
 [[package]]
 name = "mt-poly"
 version = "0.1.0"
-source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=2eb4b9d983171139af36749f127dd9890c9109e6#2eb4b9d983171139af36749f127dd9890c9109e6"
+source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa#5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa"
 dependencies = [
  "itertools 0.14.0",
  "mt-field",
@@ -3767,7 +3767,7 @@ dependencies = [
 [[package]]
 name = "mt-sumcheck"
 version = "0.1.0"
-source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=2eb4b9d983171139af36749f127dd9890c9109e6#2eb4b9d983171139af36749f127dd9890c9109e6"
+source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa#5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa"
 dependencies = [
  "mt-air",
  "mt-fiat-shamir",
@@ -3780,7 +3780,7 @@ dependencies = [
 [[package]]
 name = "mt-symetric"
 version = "0.1.0"
-source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=2eb4b9d983171139af36749f127dd9890c9109e6#2eb4b9d983171139af36749f127dd9890c9109e6"
+source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa#5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa"
 dependencies = [
  "mt-field",
  "mt-koala-bear",
@@ -3790,7 +3790,7 @@ dependencies = [
 [[package]]
 name = "mt-utils"
 version = "0.1.0"
-source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=2eb4b9d983171139af36749f127dd9890c9109e6#2eb4b9d983171139af36749f127dd9890c9109e6"
+source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa#5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa"
 dependencies = [
  "serde",
 ]
@@ -3798,7 +3798,7 @@ dependencies = [
 [[package]]
 name = "mt-whir"
 version = "0.1.0"
-source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=2eb4b9d983171139af36749f127dd9890c9109e6#2eb4b9d983171139af36749f127dd9890c9109e6"
+source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa#5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa"
 dependencies = [
  "itertools 0.14.0",
  "mt-fiat-shamir",
@@ -4048,7 +4048,7 @@ version = "0.50.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7957b9740744892f114936ab4a57b3f487491bbeafaf8083688b16841a4240e5"
 dependencies = [
- "windows-sys 0.61.2",
+ "windows-sys 0.60.2",
 ]
 
 [[package]]
@@ -4131,7 +4131,7 @@ checksum = "c08d65885ee38876c4f86fa503fb49d7b507c2b62552df7c70b2fce627e06381"
 [[package]]
 name = "p3-baby-bear"
 version = "0.5.1"
-source = "git+https://github.com/Plonky3/Plonky3.git#c7bacaeb4c870e3d6f9b7c23064c05e555c80bc8"
+source = "git+https://github.com/Plonky3/Plonky3.git#2aeaa17557e7f54b0caa0add42e7d5b9aec4f564"
 dependencies = [
  "p3-challenger",
  "p3-field",
@@ -4146,7 +4146,7 @@ dependencies = [
 [[package]]
 name = "p3-challenger"
 version = "0.5.1"
-source = "git+https://github.com/Plonky3/Plonky3.git#c7bacaeb4c870e3d6f9b7c23064c05e555c80bc8"
+source = "git+https://github.com/Plonky3/Plonky3.git#2aeaa17557e7f54b0caa0add42e7d5b9aec4f564"
 dependencies = [
  "p3-field",
  "p3-maybe-rayon",
@@ -4159,21 +4159,21 @@ dependencies = [
 [[package]]
 name = "p3-dft"
 version = "0.5.1"
-source = "git+https://github.com/Plonky3/Plonky3.git#c7bacaeb4c870e3d6f9b7c23064c05e555c80bc8"
+source = "git+https://github.com/Plonky3/Plonky3.git#2aeaa17557e7f54b0caa0add42e7d5b9aec4f564"
 dependencies = [
  "itertools 0.14.0",
  "p3-field",
  "p3-matrix",
  "p3-maybe-rayon",
  "p3-util",
- "spin 0.10.0",
+ "spin 0.11.0",
  "tracing",
 ]
 
 [[package]]
 name = "p3-field"
 version = "0.5.1"
-source = "git+https://github.com/Plonky3/Plonky3.git#c7bacaeb4c870e3d6f9b7c23064c05e555c80bc8"
+source = "git+https://github.com/Plonky3/Plonky3.git#2aeaa17557e7f54b0caa0add42e7d5b9aec4f564"
 dependencies = [
  "itertools 0.14.0",
  "num-bigint",
@@ -4188,7 +4188,7 @@ dependencies = [
 [[package]]
 name = "p3-koala-bear"
 version = "0.5.1"
-source = "git+https://github.com/Plonky3/Plonky3.git#c7bacaeb4c870e3d6f9b7c23064c05e555c80bc8"
+source = "git+https://github.com/Plonky3/Plonky3.git#2aeaa17557e7f54b0caa0add42e7d5b9aec4f564"
 dependencies = [
  "p3-challenger",
  "p3-field",
@@ -4203,7 +4203,7 @@ dependencies = [
 [[package]]
 name = "p3-matrix"
 version = "0.5.1"
-source = "git+https://github.com/Plonky3/Plonky3.git#c7bacaeb4c870e3d6f9b7c23064c05e555c80bc8"
+source = "git+https://github.com/Plonky3/Plonky3.git#2aeaa17557e7f54b0caa0add42e7d5b9aec4f564"
 dependencies = [
  "itertools 0.14.0",
  "p3-field",
@@ -4217,12 +4217,12 @@ dependencies = [
 [[package]]
 name = "p3-maybe-rayon"
 version = "0.5.1"
-source = "git+https://github.com/Plonky3/Plonky3.git#c7bacaeb4c870e3d6f9b7c23064c05e555c80bc8"
+source = "git+https://github.com/Plonky3/Plonky3.git#2aeaa17557e7f54b0caa0add42e7d5b9aec4f564"
 
 [[package]]
 name = "p3-mds"
 version = "0.5.1"
-source = "git+https://github.com/Plonky3/Plonky3.git#c7bacaeb4c870e3d6f9b7c23064c05e555c80bc8"
+source = "git+https://github.com/Plonky3/Plonky3.git#2aeaa17557e7f54b0caa0add42e7d5b9aec4f564"
 dependencies = [
  "p3-dft",
  "p3-field",
@@ -4234,7 +4234,7 @@ dependencies = [
 [[package]]
 name = "p3-monty-31"
 version = "0.5.1"
-source = "git+https://github.com/Plonky3/Plonky3.git#c7bacaeb4c870e3d6f9b7c23064c05e555c80bc8"
+source = "git+https://github.com/Plonky3/Plonky3.git#2aeaa17557e7f54b0caa0add42e7d5b9aec4f564"
 dependencies = [
  "itertools 0.14.0",
  "num-bigint",
@@ -4250,16 +4250,17 @@ dependencies = [
  "paste",
  "rand 0.10.1",
  "serde",
- "spin 0.10.0",
+ "spin 0.11.0",
  "tracing",
 ]
 
 [[package]]
 name = "p3-poseidon1"
 version = "0.5.1"
-source = "git+https://github.com/Plonky3/Plonky3.git#c7bacaeb4c870e3d6f9b7c23064c05e555c80bc8"
+source = "git+https://github.com/Plonky3/Plonky3.git#2aeaa17557e7f54b0caa0add42e7d5b9aec4f564"
 dependencies = [
  "p3-field",
+ "p3-mds",
  "p3-symmetric",
  "rand 0.10.1",
 ]
@@ -4267,7 +4268,7 @@ dependencies = [
 [[package]]
 name = "p3-poseidon2"
 version = "0.5.1"
-source = "git+https://github.com/Plonky3/Plonky3.git#c7bacaeb4c870e3d6f9b7c23064c05e555c80bc8"
+source = "git+https://github.com/Plonky3/Plonky3.git#2aeaa17557e7f54b0caa0add42e7d5b9aec4f564"
 dependencies = [
  "p3-field",
  "p3-mds",
@@ -4279,7 +4280,7 @@ dependencies = [
 [[package]]
 name = "p3-symmetric"
 version = "0.5.1"
-source = "git+https://github.com/Plonky3/Plonky3.git#c7bacaeb4c870e3d6f9b7c23064c05e555c80bc8"
+source = "git+https://github.com/Plonky3/Plonky3.git#2aeaa17557e7f54b0caa0add42e7d5b9aec4f564"
 dependencies = [
  "itertools 0.14.0",
  "p3-field",
@@ -4290,7 +4291,7 @@ dependencies = [
 [[package]]
 name = "p3-util"
 version = "0.5.1"
-source = "git+https://github.com/Plonky3/Plonky3.git#c7bacaeb4c870e3d6f9b7c23064c05e555c80bc8"
+source = "git+https://github.com/Plonky3/Plonky3.git#2aeaa17557e7f54b0caa0add42e7d5b9aec4f564"
 dependencies = [
  "serde",
  "transpose",
@@ -5054,7 +5055,7 @@ dependencies = [
 [[package]]
 name = "rec_aggregation"
 version = "0.1.0"
-source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=2eb4b9d983171139af36749f127dd9890c9109e6#2eb4b9d983171139af36749f127dd9890c9109e6"
+source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa#5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa"
 dependencies = [
  "backend",
  "lean_compiler",
@@ -5362,7 +5363,7 @@ dependencies = [
  "errno",
  "libc",
  "linux-raw-sys 0.12.1",
- "windows-sys 0.61.2",
+ "windows-sys 0.60.2",
 ]
 
 [[package]]
@@ -5793,7 +5794,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3a766e1110788c36f4fa1c2b71b387a7815aa65f88ce0229841826633d93723e"
 dependencies = [
  "libc",
- "windows-sys 0.61.2",
+ "windows-sys 0.60.2",
 ]
 
 [[package]]
@@ -5819,9 +5820,9 @@ dependencies = [
 
 [[package]]
 name = "spin"
-version = "0.10.0"
+version = "0.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d5fe4ccb98d9c292d56fec89a5e07da7fc4cf0dc11e156b41793132775d3e591"
+checksum = "783f3f6f6b01e295a669edfc402133a5f2553d1f0e81284b3ba4594e80bdd4a2"
 dependencies = [
  "lock_api",
 ]
@@ -5962,7 +5963,7 @@ dependencies = [
 [[package]]
 name = "sub_protocols"
 version = "0.1.0"
-source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=2eb4b9d983171139af36749f127dd9890c9109e6#2eb4b9d983171139af36749f127dd9890c9109e6"
+source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa#5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa"
 dependencies = [
  "backend",
  "lean_vm",
@@ -6084,7 +6085,7 @@ dependencies = [
  "getrandom 0.4.2",
  "once_cell",
  "rustix 1.1.4",
- "windows-sys 0.61.2",
+ "windows-sys 0.60.2",
 ]
 
 [[package]]
@@ -6652,7 +6653,7 @@ checksum = "06abde3611657adf66d383f00b093d7faecc7fa57071cce2578660c9f1010821"
 [[package]]
 name = "utils"
 version = "0.1.0"
-source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=2eb4b9d983171139af36749f127dd9890c9109e6#2eb4b9d983171139af36749f127dd9890c9109e6"
+source = "git+https://github.com/leanEthereum/leanMultisig.git?rev=5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa#5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa"
 dependencies = [
  "backend",
  "tracing",
diff --git a/lean_client/Cargo.toml b/lean_client/Cargo.toml
index 5f05c80e..eb0d3e68 100644
--- a/lean_client/Cargo.toml
+++ b/lean_client/Cargo.toml
@@ -251,9 +251,9 @@ indexmap = "2"
 http-body-util = "0.1"
 http_api_utils = { git = "https://github.com/grandinetech/grandine", rev = "64afdee3c6be79fceffb66933dcb69a943f3f1ae" }
 k256 = "0.13"
-rec_aggregation = { git = "https://github.com/leanEthereum/leanMultisig.git", rev = "2eb4b9d983171139af36749f127dd9890c9109e6" }
-leansig = { git = "https://github.com/leanEthereum/leanSig", branch = "devnet4" }
-leansig_wrapper = { git = "https://github.com/leanEthereum/leanMultisig.git", rev = "2eb4b9d983171139af36749f127dd9890c9109e6" }
+rec_aggregation = { git = "https://github.com/leanEthereum/leanMultisig.git", rev = "5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa" }
+leansig = { git = "https://github.com/leanEthereum/leanSig" }
+leansig_wrapper = { git = "https://github.com/leanEthereum/leanMultisig.git", rev = "5eba3b141455349d7cdbf0f5d3ccfb2e640b02aa" }
 libp2p = { version = "0.56.0", default-features = false, features = [
     'dns',
     'gossipsub',
diff --git a/lean_client/containers/src/state.rs b/lean_client/containers/src/state.rs
index b345fd78..ea7d79b2 100644
--- a/lean_client/containers/src/state.rs
+++ b/lean_client/containers/src/state.rs
@@ -108,6 +108,23 @@ impl JustifiedSlots {
     }
 }
 
+fn attestation_data_matches_chain(
+    attestation_data: &AttestationData,
+    historical_block_hashes: &[H256],
+) -> bool {
+    if attestation_data.source.root.is_zero() || attestation_data.target.root.is_zero() {
+        return false;
+    }
+    let source_slot = attestation_data.source.slot.0 as usize;
+    let target_slot = attestation_data.target.slot.0 as usize;
+    if source_slot >= historical_block_hashes.len() || target_slot >= historical_block_hashes.len()
+    {
+        return false;
+    }
+    historical_block_hashes[source_slot] == attestation_data.source.root
+        && historical_block_hashes[target_slot] == attestation_data.target.root
+}
+
 #[derive(Clone, Debug, Ssz, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct State {
@@ -653,11 +670,10 @@ impl State {
         Vec<AggregatedSignatureProof>,
     )> {
         let mut selected: Vec<(AggregatedAttestation, AggregatedSignatureProof)> = Vec::new();
+        let mut child_payloads_consumed: u64 = 0;
+        let mut processed_data_roots_count: usize = 0;
 
         if !aggregated_payloads.is_empty() {
-            // Genesis edge case: process_block_header rebinds latest_justified.root
-            // to parent_root when building on slot 0. Apply the same derivation
-            // here so attestation sources match.
             let mut current_justified = if self.latest_block_header.slot == Slot(0) {
                 Checkpoint {
                     root: parent_root,
@@ -667,7 +683,23 @@ impl State {
                 self.latest_justified.clone()
             };
 
-            // Sort by target.slot for deterministic processing order.
+            let mut current_finalized_slot = self.latest_finalized.slot;
+            let mut current_justified_slots = self
+                .justified_slots
+                .clone()
+                .extend_to_slot(current_finalized_slot, Slot(slot.0.saturating_sub(1)));
+
+            let parent_slot = self.latest_block_header.slot.0 as usize;
+            let num_empty_slots = (slot.0 as usize).saturating_sub(parent_slot + 1);
+            let mut extended_historical_block_hashes: Vec<H256> = (&self.historical_block_hashes)
+                .into_iter()
+                .copied()
+                .collect();
+            extended_historical_block_hashes.push(parent_root);
+            for _ in 0..num_empty_slots {
+                extended_historical_block_hashes.push(H256::zero());
+            }
+
             let mut sorted_entries: Vec<(
                 &H256,
                 &(AttestationData, Vec<AggregatedSignatureProof>),
@@ -677,6 +709,11 @@ impl State {
             let mut processed_data_roots: HashSet<H256> = HashSet::new();
 
             loop {
+                let select_timer = METRICS.get().map(|m| {
+                    m.lean_block_proposal_attestation_build_phase_seconds
+                        .with_label_values(&["select_payloads"])
+                        .start_timer()
+                });
                 let mut found_new = false;
 
                 for &(data_root, (att_data, proofs)) in &sorted_entries {
@@ -689,7 +726,25 @@ impl State {
                     if !known_block_roots.contains(&att_data.head.root) {
                         continue;
                     }
-                    if att_data.source != current_justified {
+
+                    if !attestation_data_matches_chain(att_data, &extended_historical_block_hashes)
+                    {
+                        continue;
+                    }
+
+                    if !current_justified_slots
+                        .is_slot_justified(current_finalized_slot, att_data.source.slot)?
+                    {
+                        continue;
+                    }
+
+                    let is_genesis_self_vote =
+                        att_data.source.slot == Slot(0) && att_data.target.slot == Slot(0);
+
+                    if !is_genesis_self_vote
+                        && current_justified_slots
+                            .is_slot_justified(current_finalized_slot, att_data.target.slot)?
+                    {
                         continue;
                     }
 
@@ -697,6 +752,7 @@ impl State {
                     found_new = true;
 
                     let indices = AggregatedSignatureProof::select_greedily(proofs);
+                    child_payloads_consumed += indices.len() as u64;
                     for idx in indices {
                         let proof = proofs[idx].clone();
                         selected.push((
@@ -709,11 +765,18 @@ impl State {
                     }
                 }
 
+                drop(select_timer);
+
                 if !found_new {
                     break;
                 }
 
-                // Run STF on a candidate block to see if justification advanced.
+                let stf_timer = METRICS.get().map(|m| {
+                    m.lean_block_proposal_attestation_build_phase_seconds
+                        .with_label_values(&["stf_simulate"])
+                        .start_timer()
+                });
+
                 let candidate_attestations = AggregatedAttestations::try_from_iter(
                     selected.iter().map(|(att, _)| att.clone()),
                 )?;
@@ -728,17 +791,29 @@ impl State {
                 };
                 let post_state = self.process_slots(slot)?.process_block(&candidate_block)?;
 
-                if post_state.latest_justified != current_justified {
+                drop(stf_timer);
+
+                if post_state.latest_justified != current_justified
+                    || post_state.latest_finalized.slot != current_finalized_slot
+                {
                     current_justified = post_state.latest_justified;
+                    current_justified_slots = post_state.justified_slots.clone();
+                    current_finalized_slot = post_state.latest_finalized.slot;
                 } else {
                     break;
                 }
             }
+
+            processed_data_roots_count = processed_data_roots.len();
         }
 
-        // Compact: merge proofs sharing the same AttestationData via recursive
-        // aggregation so each AttestationData appears at most once in the body.
+        let compact_timer = METRICS.get().map(|m| {
+            m.lean_block_proposal_attestation_build_phase_seconds
+                .with_label_values(&["compact"])
+                .start_timer()
+        });
         let compacted = self.compact_proofs_by_data(selected, log_inv_rate)?;
+        drop(compact_timer);
 
         METRICS.get().map(|metrics| {
             metrics
@@ -754,6 +829,16 @@ impl State {
         let (aggregated_attestations, aggregated_signatures): (Vec<_>, Vec<_>) =
             compacted.into_iter().unzip();
 
+        METRICS.get().map(|m| {
+            m.lean_block_proposal_attestation_builds_total.inc();
+            m.lean_block_proposal_child_payloads_consumed_total
+                .inc_by(child_payloads_consumed);
+            m.lean_block_proposal_attestation_data_selected
+                .observe(processed_data_roots_count as f64);
+            m.lean_block_proposal_aggregates_selected
+                .observe(aggregated_signatures.len() as f64);
+        });
+
         let mut final_block = Block {
             slot,
             proposer_index,
diff --git a/lean_client/fork_choice/src/store.rs b/lean_client/fork_choice/src/store.rs
index 20c60f5e..17006560 100644
--- a/lean_client/fork_choice/src/store.rs
+++ b/lean_client/fork_choice/src/store.rs
@@ -695,12 +695,16 @@ pub fn execute_block_production(
         "proposer block built"
     );
 
-    ensure!(
-        final_post_state.latest_justified.slot >= store_latest_justified.slot,
-        "Produced block justified={} < store justified={}. Fixed-point attestation loop did not converge.",
-        final_post_state.latest_justified.slot.0,
-        store_latest_justified.slot.0,
-    );
+    if final_post_state.latest_justified.slot < store_latest_justified.slot {
+        warn!(
+            produced = final_post_state.latest_justified.slot.0,
+            store = store_latest_justified.slot.0,
+            "Produced block justified < store justified. Fixed-point did not converge."
+        );
+        METRICS
+            .get()
+            .map(|m| m.lean_build_block_fixed_point_no_converge_total.inc());
+    }
 
     let block_root = final_block.hash_tree_root();
 
diff --git a/lean_client/fork_choice/tests/unit_tests/common.rs b/lean_client/fork_choice/tests/unit_tests/common.rs
index bdc7b53a..11b6a92d 100644
--- a/lean_client/fork_choice/tests/unit_tests/common.rs
+++ b/lean_client/fork_choice/tests/unit_tests/common.rs
@@ -22,5 +22,5 @@ pub fn create_test_store() -> Store {
         signature: Default::default(),
     };
 
-    get_forkchoice_store(state, signed_block, config)
+    get_forkchoice_store(state, signed_block, config, true)
 }
diff --git a/lean_client/fork_choice/tests/unit_tests/validator.rs b/lean_client/fork_choice/tests/unit_tests/validator.rs
index dbee9fa0..dde00b71 100644
--- a/lean_client/fork_choice/tests/unit_tests/validator.rs
+++ b/lean_client/fork_choice/tests/unit_tests/validator.rs
@@ -7,12 +7,15 @@ use std::collections::HashMap;
 use crate::unit_tests::common::create_test_store;
 use containers::{
     AggregatedSignatureProof, AggregationBits, Attestation, AttestationData, Block, BlockBody,
-    Checkpoint, Config, SignedBlock, Slot, State, Validator,
+    BlockSignatures, Checkpoint, Config, SignedBlock, Slot, State, Validator,
 };
+use fork_choice::block_cache::BlockCache;
+use fork_choice::handlers::on_block;
 use fork_choice::store::{Store, get_forkchoice_store, produce_block_with_signatures, update_head};
 use rand::SeedableRng;
 use rand_chacha::ChaChaRng;
 use ssz::{H256, SszHash};
+use std::collections::HashSet;
 use xmss::SecretKey;
 
 /// Build an `AggregatedSignatureProof` for the given validator set on the
@@ -109,7 +112,10 @@ fn create_test_store_with_signers() -> (Store, HashMap<u64, SecretKey>) {
         signature: Default::default(),
     };
 
-    (get_forkchoice_store(state, signed_block, config), keys)
+    (
+        get_forkchoice_store(state, signed_block, config, true),
+        keys,
+    )
 }
 // ---------------------------------------------------------------------------
 // TestBlockProduction
@@ -489,7 +495,7 @@ fn test_validator_operations_empty_store() {
         signature: Default::default(),
     };
 
-    let mut store = get_forkchoice_store(state, signed_block, config);
+    let mut store = get_forkchoice_store(state, signed_block, config, true);
 
     // Should be able to produce block and attestation
     let (_root, block, _sig) =
@@ -606,3 +612,175 @@ fn test_produce_attestation_data_uses_head_state_justified() {
     assert_eq!(attestation_data.source, expected_source);
     assert_ne!(attestation_data.source, store.latest_justified);
 }
+
+fn produce_and_apply(
+    store: &mut Store,
+    cache: &mut BlockCache,
+    slot: Slot,
+    keys: &HashMap<u64, SecretKey>,
+) -> H256 {
+    let num_validators = store.states[&store.head].validators.len_u64();
+    let proposer = slot.0 % num_validators;
+    let _ = keys;
+    let (_block_root, block, _sigs) =
+        produce_block_with_signatures(store, slot, proposer, 1).expect("block production failed");
+    let signed = SignedBlock {
+        block,
+        signature: BlockSignatures::default(),
+    };
+    let block_root = signed.block.hash_tree_root();
+    on_block(store, cache, signed, false).expect("on_block failed");
+    block_root
+}
+
+#[test]
+fn test_produce_block_closes_justification_gap() {
+    let (mut store, keys) = create_test_store_with_signers();
+    let mut cache = BlockCache::new();
+    let num_validators = store.states[&store.head].validators.len_u64();
+    let genesis_root = store.head;
+    let genesis_ckpt = Checkpoint {
+        root: genesis_root,
+        slot: Slot(0),
+    };
+
+    let block_1_root = produce_and_apply(&mut store, &mut cache, Slot(1), &keys);
+    let block_2_root = produce_and_apply(&mut store, &mut cache, Slot(2), &keys);
+    let block_3_root = produce_and_apply(&mut store, &mut cache, Slot(3), &keys);
+
+    let block_1_ckpt = Checkpoint {
+        root: block_1_root,
+        slot: Slot(1),
+    };
+    let block_2_ckpt = Checkpoint {
+        root: block_2_root,
+        slot: Slot(2),
+    };
+    let block_3_ckpt = Checkpoint {
+        root: block_3_root,
+        slot: Slot(3),
+    };
+
+    let att_target_block_1 = AttestationData {
+        slot: Slot(4),
+        head: block_3_ckpt.clone(),
+        target: block_1_ckpt.clone(),
+        source: genesis_ckpt.clone(),
+    };
+    publish_aggregated_payload(
+        &mut store,
+        &att_target_block_1,
+        &[0, 1, 2, 3, 4, 5, 6],
+        &keys,
+    );
+
+    let block_4_root = produce_and_apply(&mut store, &mut cache, Slot(4), &keys);
+    let block_4_ckpt = Checkpoint {
+        root: block_4_root,
+        slot: Slot(4),
+    };
+    assert_eq!(store.latest_justified, block_1_ckpt);
+
+    let att_target_block_4 = AttestationData {
+        slot: Slot(5),
+        head: block_4_ckpt.clone(),
+        target: block_4_ckpt.clone(),
+        source: block_1_ckpt.clone(),
+    };
+    publish_aggregated_payload(&mut store, &att_target_block_4, &[7, 8], &keys);
+
+    let block_5_root = produce_and_apply(&mut store, &mut cache, Slot(5), &keys);
+    assert_eq!(store.latest_justified, block_1_ckpt);
+    assert_eq!(store.head, block_5_root);
+
+    let att_target_block_2 = AttestationData {
+        slot: Slot(6),
+        head: block_3_ckpt.clone(),
+        target: block_2_ckpt.clone(),
+        source: genesis_ckpt.clone(),
+    };
+    publish_aggregated_payload(
+        &mut store,
+        &att_target_block_2,
+        &[0, 1, 2, 3, 4, 5, 6],
+        &keys,
+    );
+
+    let block_3_state = store
+        .states
+        .get(&block_3_root)
+        .expect("block_3 state missing")
+        .clone();
+    let known_block_roots: HashSet<H256> = store.blocks.keys().copied().collect();
+    let aggregated_payloads: HashMap<H256, (AttestationData, Vec<AggregatedSignatureProof>)> =
+        store
+            .latest_known_aggregated_payloads
+            .iter()
+            .filter_map(|(root, proofs)| {
+                store
+                    .attestation_data_by_root
+                    .get(root)
+                    .map(|data| (*root, (data.clone(), proofs.clone())))
+            })
+            .collect();
+    let proposer_6 = Slot(6).0 % num_validators;
+    let (block_6, _post_state_6, _atts_6, _sigs_6) = block_3_state
+        .build_block(
+            Slot(6),
+            proposer_6,
+            block_3_root,
+            &known_block_roots,
+            &aggregated_payloads,
+            1,
+        )
+        .expect("build_block for sibling block_6 failed");
+    let signed_block_6 = SignedBlock {
+        block: block_6,
+        signature: BlockSignatures::default(),
+    };
+    let block_6_root = signed_block_6.block.hash_tree_root();
+    on_block(&mut store, &mut cache, signed_block_6, false).expect("on_block for block_6 failed");
+
+    assert_eq!(store.latest_justified, block_2_ckpt);
+    assert_eq!(store.head, block_5_root);
+
+    let gap_closers: Vec<&AttestationData> = store
+        .latest_known_aggregated_payloads
+        .keys()
+        .filter_map(|root| store.attestation_data_by_root.get(root))
+        .filter(|d| d.target == block_2_ckpt)
+        .collect();
+    assert_eq!(gap_closers.len(), 1);
+    assert_eq!(gap_closers[0].source, genesis_ckpt);
+    assert_eq!(gap_closers[0].slot, Slot(6));
+
+    let proposer_7 = Slot(7).0 % num_validators;
+    let (_block_7_root, block_7, _sigs_7) =
+        produce_block_with_signatures(&mut store, Slot(7), proposer_7, 1)
+            .expect("block production for block_7 failed");
+
+    assert_eq!(block_7.parent_root, block_5_root);
+
+    let body_targets: Vec<Checkpoint> = (0..block_7.body.attestations.len_usize())
+        .map(|i| {
+            block_7
+                .body
+                .attestations
+                .get(i as u64)
+                .expect("missing attestation")
+                .data
+                .target
+                .clone()
+        })
+        .collect();
+    assert!(body_targets.contains(&block_2_ckpt));
+
+    let signed_block_7 = SignedBlock {
+        block: block_7,
+        signature: BlockSignatures::default(),
+    };
+    on_block(&mut store, &mut cache, signed_block_7, false).expect("on_block for block_7 failed");
+    assert_eq!(store.latest_justified, block_2_ckpt);
+
+    let _ = block_6_root;
+}
diff --git a/lean_client/metrics/src/metrics.rs b/lean_client/metrics/src/metrics.rs
index cbd8cc44..50148821 100644
--- a/lean_client/metrics/src/metrics.rs
+++ b/lean_client/metrics/src/metrics.rs
@@ -3,7 +3,8 @@ use std::{sync::Arc, time::SystemTime};
 use anyhow::{Context, Result};
 use once_cell::sync::OnceCell;
 use prometheus::{
-    GaugeVec, Histogram, IntCounter, IntCounterVec, IntGauge, IntGaugeVec, histogram_opts, opts,
+    GaugeVec, Histogram, HistogramVec, IntCounter, IntCounterVec, IntGauge, IntGaugeVec,
+    histogram_opts, opts,
 };
 
 pub static METRICS: OnceCell<Arc<Metrics>> = OnceCell::new();
@@ -194,6 +195,12 @@ pub struct Metrics {
     /// the data_root present in `latest_known_aggregated_payloads`. Drift
     /// between the two maps would silently shrink the proposer's pool.
     pub lean_build_block_pool_missing_att_data: IntCounter,
+    pub lean_build_block_fixed_point_no_converge_total: IntCounter,
+    pub lean_block_proposal_attestation_build_phase_seconds: HistogramVec,
+    pub lean_block_proposal_attestation_builds_total: IntCounter,
+    pub lean_block_proposal_child_payloads_consumed_total: IntCounter,
+    pub lean_block_proposal_attestation_data_selected: Histogram,
+    pub lean_block_proposal_aggregates_selected: Histogram,
 
     /// Snapshot size at clone time, measured in total entries across the largest
     /// Store maps (blocks + states + gossip_signatures + known_aggregated_payloads
@@ -534,6 +541,38 @@ impl Metrics {
                 "lean_build_block_pool_missing_att_data",
                 "Total payload entries dropped at proposal time because attestation_data_by_root has no entry for the data_root",
             )?,
+            lean_build_block_fixed_point_no_converge_total: IntCounter::new(
+                "lean_build_block_fixed_point_no_converge_total",
+                "Total build_block calls where the produced block's latest_justified did not reach the store's latest_justified",
+            )?,
+            lean_block_proposal_attestation_build_phase_seconds: HistogramVec::new(
+                histogram_opts!(
+                    "lean_block_proposal_attestation_build_phase_seconds",
+                    "Phase-level time in block-proposal attestation selection (build_block): select_payloads, compact, stf_simulate",
+                    vec![
+                        0.001, 0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0
+                    ]
+                ),
+                &["phase"],
+            )?,
+            lean_block_proposal_attestation_builds_total: IntCounter::new(
+                "lean_block_proposal_attestation_builds_total",
+                "Completed block-proposal attestation selection runs (one per proposal attempt)",
+            )?,
+            lean_block_proposal_child_payloads_consumed_total: IntCounter::new(
+                "lean_block_proposal_child_payloads_consumed_total",
+                "Child aggregated payloads selected during greedy proof picking (before recursive compaction)",
+            )?,
+            lean_block_proposal_attestation_data_selected: Histogram::with_opts(histogram_opts!(
+                "lean_block_proposal_attestation_data_selected",
+                "Distinct AttestationData entries in the proposal block body",
+                vec![0.0, 1.0, 2.0, 4.0, 8.0, 16.0, 32.0]
+            ))?,
+            lean_block_proposal_aggregates_selected: Histogram::with_opts(histogram_opts!(
+                "lean_block_proposal_aggregates_selected",
+                "Aggregated signature proofs in the proposal result after compaction",
+                vec![0.0, 1.0, 2.0, 4.0, 8.0, 16.0, 32.0, 64.0, 128.0]
+            ))?,
             lean_aggregation_snapshot_size_entries: Histogram::with_opts(histogram_opts!(
                 "lean_aggregation_snapshot_size_entries",
                 "Total entries across all major Store maps at snapshot clone time",
@@ -785,6 +824,26 @@ impl Metrics {
         default_registry.register(Box::new(
             self.lean_build_block_pool_missing_att_data.clone(),
         ))?;
+        default_registry.register(Box::new(
+            self.lean_build_block_fixed_point_no_converge_total.clone(),
+        ))?;
+        default_registry.register(Box::new(
+            self.lean_block_proposal_attestation_build_phase_seconds
+                .clone(),
+        ))?;
+        default_registry.register(Box::new(
+            self.lean_block_proposal_attestation_builds_total.clone(),
+        ))?;
+        default_registry.register(Box::new(
+            self.lean_block_proposal_child_payloads_consumed_total
+                .clone(),
+        ))?;
+        default_registry.register(Box::new(
+            self.lean_block_proposal_attestation_data_selected.clone(),
+        ))?;
+        default_registry.register(Box::new(
+            self.lean_block_proposal_aggregates_selected.clone(),
+        ))?;
         default_registry.register(Box::new(
             self.lean_aggregation_snapshot_size_entries.clone(),
         ))?;
diff --git a/lean_client/xmss/src/secret_key.rs b/lean_client/xmss/src/secret_key.rs
index 50a449ce..ba93b51c 100644
--- a/lean_client/xmss/src/secret_key.rs
+++ b/lean_client/xmss/src/secret_key.rs
@@ -3,7 +3,7 @@ use derive_more::Debug;
 use leansig::serialization::Serializable;
 use leansig::signature::SignatureScheme;
 use leansig::signature::generalized_xmss::instantiations_aborting::lifetime_2_to_the_32::{
-    SchemeAbortingTargetSumLifetime32Dim46Base8 as XmssScheme,
+    SIGAbortingTargetSumLifetime32Dim46Base8 as XmssScheme,
     SecretKeyAbortingTargetSumLifetime32Dim46Base8 as XmssSecretKey,
 };
 use rand::CryptoRng;