Notifications marked as read on the old instance are displayed as unread after upgrade

STEPS TO REPRODUCE

Preconditions: Have an older instance of XWiki (e.g. 11.10.11) with an user that has some (unread) notifications in the list.

1. Login as the user
2. Mark some notifications as read
3. Close the instance
4. Go to the newer instance (e.g. 12.9) and copy/cut the

   [...]webapps\xwiki

   folder and replace it (first delete the old one) in the same location on the older version

1. Start XWiki and follow DW
2. On 'Step 5 - Events migration' migrate events from 'All time'
3. Login with the user U1
4. Observe the notifications list

EXPECTED RESULTS

The events from notifications list marked as read on the old instance are marked as read as well on the upgraded version.

ACTUAL RESULTS

The events are displayed as unread.

The issue reproduces also on XWiki 12.6.4 and does not reproduce when upgrading an instance from XWiki 11.10.11 to XWiki 12.4.