diff --git a/mongo/bulk_write.go b/mongo/bulk_write.go
index df9d4eb4c..ebd02d0ec 100644
--- a/mongo/bulk_write.go
+++ b/mongo/bulk_write.go
@@ -69,7 +69,10 @@ func (bw *bulkWrite) execute(ctx context.Context) error {
 
 		bw.mergeResults(batchRes)
 
-		bwErr.WriteConcernError = batchErr.WriteConcernError
+		if bwErr.WriteConcernError == nil {
+			bwErr.WriteConcernError = batchErr.WriteConcernError
+		}
+
 		bwErr.Labels = append(bwErr.Labels, batchErr.Labels...)
 
 		bwErr.WriteErrors = append(bwErr.WriteErrors, batchErr.WriteErrors...)