Notifications are not (always) automatically loaded in the list on Internet Explorer 11

STEPS TO REPRODUCE

1. Login as Admin
2. Create an user (e.g. U1)
3. Login as U1
4. Go to Notifications > Settings and set Pages Notifications to ON
5. Login as Admin
6. Create/update/comment a page (e.g. Pag1)
7. Login as U1
8. Observe the notification list
9. Login again as Admin
10. Create/update/comment another page (e.g. Pag2)
11. Login as U1
12. Observe the notification list

EXPECTED RESULTS

In the notification list there are 6 event notifications.

ACTUAL RESULTS

There are displayed only the first 3 event notifications, the rest of them are not loaded unless a force refresh (CTRL+F5) is performed on the page. The issue could be reproduced only on IE11 browser (even after clearing cache manually).