I don't especially like this, for several reasons.
It's kinda making an assumption about the problem that may not be warranted. Sure, sometimes one person is the problem, but sometimes you've got an issue where several people are responsible, or the asker could accept an answer that indicates that they themselves were the problem or that no one is particularly to blame. Tags that only really unambiguously apply after a question has been definitively answered are... not very good tags.
It's loaded language. Saying that someone is a "problem player" or "problem GM" is making the gaming problem a the identity of a person rather than just their behavior.
(Minor) I feel like these are making structural assumptions about the game that don't fit all games.
How about group-problems instead?