diff --git a/consensus/state_processing/src/per_block_processing/signature_sets.rs b/consensus/state_processing/src/per_block_processing/signature_sets.rs
index 4e83ec95fe..4e56e8eaff 100644
--- a/consensus/state_processing/src/per_block_processing/signature_sets.rs
+++ b/consensus/state_processing/src/per_block_processing/signature_sets.rs
@@ -378,10 +378,14 @@ where
         .data
         .slot
         .epoch(E::slots_per_epoch());
+    // Use config-based fork lookup rather than state.fork() to avoid
+    // race conditions during fork transitions where the head state
+    // may not yet reflect the new fork.
+    let fork = spec.fork_at_epoch(epoch);
     let domain = spec.get_domain(
         epoch,
         Domain::PTCAttester,
-        &state.fork(),
+        &fork,
         state.genesis_validators_root(),
     );