this also happened to me, must be a bug/glitch.

The leader boards are frozen for you. I also have that same problem on that map. Treyarch has to fix it, Hope this helped

Have you gotten higher than round 37 before? If so, it won't change until you beat that round. Did you lag out or did the host leave? If either of the two happened it won't save. If you play solo it won't save it on the leaderboards either.

Yeah I have this problem none of my rounds will save no matter what map and even though I have the highest round on Ascension on my friend list I am still at the bottom of the leader board with negative time eg -2minutes

Can anyone help?x

Me and a lot of friends have the same problem with Nacht. Did you by chance use the barrier glitch? I feel that might have something to do with it. If not then its just treyarch not fixing a glitch

I have the same problem with kino, five and all the classic maps except der reise.
Some maps show my highest score but not my rounds.
The leaderboards are screwed I'm afraid

My leaderboards are stuck on round 99 for everyone... Hope this gets fixed.