I have had the same problem. My notifications spammed!

Me too!

I also experienced this issue, with a few other badges as well. It is most like Khan Academy doing work on the badges / updating something relating to them, so there shouldn't be anything to worry about unless you start losing badges. In that case, definitely notify the team by submitting a ticket.

I bet this badge is "healthy" now.

It is good thing I got so much new badges, but then they suddenly gone waste --- who knows where?