diff --git a/CHANGELOG.md b/CHANGELOG.md
index aa5723a..0481948 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,21 @@
 
 > **Note:** Versions 0.3.26 – 0.3.55 were released as git tags without changelog entries. Changelog resumes at 0.3.56 below.
 
+## 0.5.6
+
+### Fixed
+
+- **Apply 1s stale-prior threshold to `_createPeer` path.** v0.5.5
+  lowered the threshold to 1s in the inbound-connection handler but
+  left the `_createPeer` path on the old `_heartbeatInterval` (10s).
+  When both sides of a peer pair dialled each other in rapid
+  succession, the inbound handler accepted with the 1s rule but the
+  merged `_createPeer` re-evaluated with 10s and could pick the
+  opposite winner. Mac-side and Node-side then kept different
+  connections, each killing the other's choice — visible in field
+  testing as a continuous ~6s join → disconnect cycle even after
+  v0.5.5. Aligned both sites on 1s.
+
 ## 0.5.5
 
 ### Fixed
diff --git a/lib/node.js b/lib/node.js
index 997b22f..2c54926 100644
--- a/lib/node.js
+++ b/lib/node.js
@@ -1208,8 +1208,15 @@ class SymNode extends EventEmitter {
       //       nodeId acts as client and keeps outbound; higher keeps inbound
       const existingTransport = existingPeer.transports.get(source);
       const staleByFlag = !existingTransport || existingTransport._closed;
+      // Match the inbound-connection handler (v0.5.5): a 1s threshold catches
+      // peer process restarts (kill + quick re-dial) without rejecting
+      // genuine dual-dial collisions, which fire <100ms apart. The previous
+      // _heartbeatInterval (10s) caused dedup-decisions to diverge across
+      // SDKs — Node-side rejected as stale while sym-swift kept the prior,
+      // so the surviving connection on one side was already dead on the
+      // other and the peer flapped continuously.
       const staleByLastSeen = existingPeer.lastSeen
-        && (Date.now() - existingPeer.lastSeen) > this._heartbeatInterval;
+        && (Date.now() - existingPeer.lastSeen) > 1000;
       const stalePrior = staleByFlag || staleByLastSeen;
       if (existingTransport && !stalePrior) {
         const prevIsOutbound = !!existingPeer.isOutbound;
diff --git a/package.json b/package.json
index 038b09f..a31d0da 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@sym-bot/sym",
-  "version": "0.5.5",
+  "version": "0.5.6",
   "description": "Infrastructure and protocol for multi-agent collective intelligence",
   "main": "lib/node.js",
   "bin": {