Halfway through level 60, stopped gaining xp

I played through TVHM and went to the fustercluck dlc. Turned mayhem to 10 and then I stopped gaining XP. I’m still getting xp for guardian though. my xp bar is halfway between 60 and 61

It could be that the hotfix wasn’t properly applied. Verify integrity of game files and see if that works out for you. There’s a similar kind of option on epic too.