One thing I noticed - it currently doesn’t pull all unread notifications. It only filters the first loaded ‘page’ of them, but if you have more unread ones in the past, you have to scroll down in the All view and only then switch to unread ones.
It would be fun if switching to Unread filter would load all unread notifications and not just the unread ones from the first page, if that makes sense 
EDIT.
I’ve just found out another bug, I think.
When you middle click in this view:
It should open a topic in a new tab, but instead it clears the notification without opening any new tabs.