have you done any quests, dungeon runs or anything since you reached 100%? maybe you need just small amount of xp that's less then 0,01%, so it's not visible ... you have high level, so it's possible you just need very little to level up

Hey Klova, i did several runs in 12-5 since and fought in the arena.

Edit: Thx for help, one more run and proceeded to level 57