Do troublemakers prevent single problem faceoffs?
In the comprehensive rules, rule 611.4 says


  As a player confronts a Problem, that player scores a point. If an opponent also meets their confront requirements for that Problem (611.3), there will be a Problem Faceoff at that Problem.


And rule 611.3e says


  A player can’t confront a Problem if there is an opposing face-up Troublemaker or a face-up Troublemaker with Villain at that Problem.


611.4's reference back to 611.3 implies that there would be no faceoff (in accordance with the basic rules, whew), as the same confront requirements (611.3e) are needed unless there is a double problem faceoff.