diff --git a/lighthouse/state/attestation_record/validation/message_generation.rs b/lighthouse/state/attestation_record/validation/message_generation.rs
index da6dd2e497..3bcc4c16a8 100644
--- a/lighthouse/state/attestation_record/validation/message_generation.rs
+++ b/lighthouse/state/attestation_record/validation/message_generation.rs
@@ -23,9 +23,7 @@ pub fn generate_signed_message(slot: u64,
      */
     let mut ssz_stream = SszStream::new();
     ssz_stream.append(&slot);
-    for h in parent_hashes {
-        ssz_stream.append_encoded_raw(&h.to_vec())
-    }
+    ssz_stream.append_vec(&parent_hashes.to_vec());
     ssz_stream.append(&shard_id);
     ssz_stream.append(shard_block_hash);
     ssz_stream.append(&justified_slot);