There has been a months-long bug with Notifications, which means it’s become something of a lottery as to when you get informed about when you get tagged in an answer.
If you’re actually looking for bad news, it’s that it’s still impossible to tell when you’ve been mentioned in a comment if you don’t get notified. For now, comments remain part of the dark underground.
Now, this is paranoid thinking. Of course it is.
But there’s been a whole barrage of UX changes recently, that have deprecated interaction between users on the platform.
And this unpredictability of notifications of @-mentions has been in place for months. It got several mentions on the late, lamented Rage Against Quora.