I had the same issue yesterday... had the required xp + 300 extra points to advance to level 100 ... thought I would have to email WGT about the problem, but the next game I started, right after my tee shot hit the first green on Bandon, the level up notification hit my screen so it maybe that there is a glitch in the cyber math on their system ...
It's been known to happen to some players in the past and it looks like it's rearing it's ugly head again ...
Stay calm, play golf ... repeat as necessary!