diff --git a/beacon-chain/sync/validate_aggregate_proof.go b/beacon-chain/sync/validate_aggregate_proof.go
index fff9e4ec4b5..9b6eda8fc80 100644
--- a/beacon-chain/sync/validate_aggregate_proof.go
+++ b/beacon-chain/sync/validate_aggregate_proof.go
@@ -81,7 +81,7 @@ func (r *Service) validateAggregateAndProof(ctx context.Context, pid peer.ID, ms
 
 	// Only advance state if different epoch as the committee can only change on an epoch transition.
 	if helpers.SlotToEpoch(attSlot) > helpers.SlotToEpoch(s.Slot) {
-		s, err = state.ProcessSlots(ctx, s, attSlot)
+		s, err = state.ProcessSlots(ctx, s, helpers.StartSlot(helpers.SlotToEpoch(attSlot)))
 		if err != nil {
 			traceutil.AnnotateError(span, err)
 			return false