diff --git a/age--1.8.0--y.y.y.sql b/age--1.8.0--y.y.y.sql
index 974604dc9..c5fa679d9 100644
--- a/age--1.8.0--y.y.y.sql
+++ b/age--1.8.0--y.y.y.sql
@@ -58,10 +58,10 @@ CREATE FUNCTION ag_catalog.load_labels_from_file(graph_name name,
 DROP FUNCTION IF EXISTS ag_catalog.load_edges_from_file(name, name, text, bool);
 
 CREATE FUNCTION ag_catalog.load_edges_from_file(graph_name name,
-                                                label_name name,
-                                                file_path text,
-                                                load_as_agtype bool default false,
-                                                delimiter text default ',')
+                                                 label_name name,
+                                                 file_path text,
+                                                 load_as_agtype bool default false,
+                                                 delimiter text default ',')
     RETURNS void
     LANGUAGE c
     AS 'MODULE_PATHNAME';
@@ -100,3 +100,14 @@ BEGIN
       AND opcfamily = btree_family;
 END
 $$;
+
+--
+-- Mark agtype_string_match_starts_with/_ends_with IMMUTABLE
+--
+-- Issue #2576: same inputs always produce the same output with no catalog
+-- lookups or session state, matching agtype_string_match_contains which is
+-- already IMMUTABLE.
+
+ALTER FUNCTION ag_catalog.agtype_string_match_starts_with(agtype, agtype) IMMUTABLE;
+
+ALTER FUNCTION ag_catalog.agtype_string_match_ends_with(agtype, agtype) IMMUTABLE;
diff --git a/sql/agtype_string.sql b/sql/agtype_string.sql
index 0d7b2013f..0be44eb1b 100644
--- a/sql/agtype_string.sql
+++ b/sql/agtype_string.sql
@@ -24,7 +24,7 @@
 CREATE FUNCTION ag_catalog.agtype_string_match_starts_with(agtype, agtype)
     RETURNS agtype
     LANGUAGE c
-    STABLE
+    IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';
@@ -32,7 +32,7 @@ AS 'MODULE_PATHNAME';
 CREATE FUNCTION ag_catalog.agtype_string_match_ends_with(agtype, agtype)
     RETURNS agtype
     LANGUAGE c
-    STABLE
+    IMMUTABLE
 RETURNS NULL ON NULL INPUT
 PARALLEL SAFE
 AS 'MODULE_PATHNAME';