Some unread notification events are displayed as read in notifications list and Activity Stream and counter shows a wrong value after upgrade XWiki

STEPS TO REPRODUCE

1. Login as Admin on a XWiki 13.10.7 instance (tested with MariaDB 10.6/ Tomcat 9.0.65)
2. Create an user (e.g. U1)
3. Set notifications toggles to ON for the user U1 (e.g. for 'Pages')
4. Create a subwiki (optional, but it can be reproduced more easily with it in some cases)
5. Add the user U1 to be member of subwiki (I don't know for sure if this is needed, but that's how I tested)
6. Create, edit (I've also added/deleted some attachments), delete some pages to generate events for the user on Main as well on subwiki (I've tested with 15 events for this case)
7. Login with U1
8. Observe the (unread) notifications list and the Dashboard's Activity Stream
9. On the notifications list, mark a single event as read
10. Login as Admin
11. Upgrade the instance to XWiki 14.6 (or 14.7), Main wiki and the subwiki (e.g. by replacing the WAR and configuring it with the correct DB)
12. After the upgrade is finished, login with the user U1
13. Observe the notifications list (including the counter) and the Dashboard's Activity Stream

EXPECTED RESULTS
All notifications are marked as unread, except the single event marked as read.
The notifications list counter displays 14 events.

ACTUAL RESULTS
Some other notification events are marked as read as well, in addition to the one marked by the user initially.

The counter also displays 14, although there are only 10 unread events in the notifications list.

In some tests run, the events marked as read in notifications list were not marked as read as well in Activity Stream and also not the same events (or even type of events) were marked as read after upgrade every time.

What I've also noticed is that the Profile creation events are marked always as read after the upgrade.

The issue could not be reproduced when upgrading to XWiki 14.5.