diff --git a/specs/sharding/beacon-chain.md b/specs/sharding/beacon-chain.md
index 98feba22b..e6137748c 100644
--- a/specs/sharding/beacon-chain.md
+++ b/specs/sharding/beacon-chain.md
@@ -608,7 +608,7 @@ def process_shard_header(state: BeaconState, signed_header: SignedShardBlobHeade
     assert committee_work.status.selector == SHARD_WORK_PENDING
 
     # Check that this header is not yet in the pending list
-    current_headers: Sequence[PendingShardHeader] = committee_work.status.value
+    current_headers: MutableSequence[PendingShardHeader] = committee_work.status.value
     header_root = hash_tree_root(header)
     assert header_root not in [pending_header.root for pending_header in current_headers]
 
@@ -640,7 +640,7 @@ def process_shard_header(state: BeaconState, signed_header: SignedShardBlobHeade
     )
 
     # Include it in the pending list
-    state.shard_buffer[header.slot % SHARD_STATE_MEMORY_SLOTS][header.shard].append(pending_header)
+    current_headers.append(pending_header)
 ```
 
 The degree proof works as follows. For a block `B` with length `l` (so `l`  values in `[0...l - 1]`, seen as a polynomial `B(X)` which takes these values),