V13.13.0 Notifications Center

Hi All,
i am working on V13.13.0 and i am facing issue related to system notifications
The bell get red point to notify a new notification arrived , but nothing shown when opening the notification center.
for example, when i assign document to another user, this user get the red point on the bell, but when he click the bell, it always shows no new notifications.

also, i noticed that when creating a new user with sales user role for example, he didn’t get the bell on his desk, what i should do on the user profile to get the notifications bell appears on his desk?

thanks for your support.

am i missing something here?