Private browsing (free) yet getting user-specific profile view notifications

My account is the free version and I use private browsing. So I do not expect to ever see who views my profile or likes me.

However, I have been getting notifications on iOS saying "UserX has just viewed you!" "UserY likes you!"

It's just the notification, though, I can't go see a list of these users anywhere.

Has anyone else experienced this? Seems like a violation of the expected privacy policy. I don't know whether these accounts are all non-private browsers, but I don't think that should matter in this case.