diff --git a/extensions/mentions/js/src/forum/components/PostMentionedNotification.js b/extensions/mentions/js/src/forum/components/PostMentionedNotification.js
index 42651aa1b..6271833aa 100644
--- a/extensions/mentions/js/src/forum/components/PostMentionedNotification.js
+++ b/extensions/mentions/js/src/forum/components/PostMentionedNotification.js
@@ -23,6 +23,6 @@ export default class PostMentionedNotification extends Notification {
   }
 
   excerpt() {
-    return truncate(this.attrs.notification.subject().contentPlain(), 200);
+    return truncate(this.attrs.notification.subject().contentPlain() || '', 200);
   }
 }