diff --git a/src/lean_spec/subspecs/containers/state/state.py b/src/lean_spec/subspecs/containers/state/state.py
index d24a4d95..3326c2dc 100644
--- a/src/lean_spec/subspecs/containers/state/state.py
+++ b/src/lean_spec/subspecs/containers/state/state.py
@@ -460,7 +460,7 @@ def process_attestations(
             # This prevents votes about unknown or conflicting forks.
             if (
                 source.root != self.historical_block_hashes[source.slot]
-                and target.root != self.historical_block_hashes[target.slot]
+                or target.root != self.historical_block_hashes[target.slot]
             ):
                 continue