This happens to us too. Realtime only works sometimes or just for a minute after you load a page. If more time pass then you need to reload manually.
Do you use cloudfare?
I noticed that in the unread page, if i have some "legacy" posts that is unread, and subsequently the category is disabled, it will still remain in the unread page.
However, when one clicks on the post, it will show a 404 error.