diff --git a/src/notifications.js b/src/notifications.js
index fdb9998248..20a6cd5f73 100644
--- a/src/notifications.js
+++ b/src/notifications.js
@@ -475,7 +475,7 @@ Notifications.merge = async function (notifications) {
 				case 'notifications:user-posted-to':
 				case 'notifications:user-flagged-post-in':
 				case 'notifications:user-flagged-user': {
-					const usernames = _.uniq(set.map(notifObj => notifObj && notifObj.user && notifObj.user.username));
+					const usernames = _.uniq(set.map(notifObj => notifObj && notifObj.user && notifObj.user.displayname));
 					const numUsers = usernames.length;
 
 					const title = utils.decodeHTMLEntities(notifications[modifyIndex].topicTitle || '');