diff --git a/src/User/UserMetadataUpdater.php b/src/User/UserMetadataUpdater.php
index 19bb2e8fec..5e0252e589 100644
--- a/src/User/UserMetadataUpdater.php
+++ b/src/User/UserMetadataUpdater.php
@@ -65,7 +65,7 @@ public function whenDiscussionWasDeleted(DiscussionDeleted $event)
     /**
      * @param \Flarum\User\User $user
      */
-    private function updateCommentsCount(User $user)
+    private function updateCommentsCount(?User $user)
     {
         if ($user && $user->exists) {
             $user->refreshCommentCount()->save();