diff --git a/module/gitlab/model.php b/module/gitlab/model.php
index a28ed01c40..e6c23f6ab4 100644
--- a/module/gitlab/model.php
+++ b/module/gitlab/model.php
@@ -865,6 +865,8 @@ class gitlabModel extends model
             }
             if($value) $issue->$field = $value;
         }
+
+        if($issue->assignee_id == 'closed') unset($issue->assignee_id);
         /* issue->state is null when creating it, we should put status_event when updating it. */
         if(isset($issue->state) and $issue->state == 'closed') $issue->state_event='close';
         if(isset($issue->state) and $issue->state == 'opened') $issue->state_event='reopen';