KPJ missed a big chunk of his only season at USC due to a suspension for conduct detrimental to the team which caused him to fall to the end of the first round in the draft.
He got arrested while playing for Cleveland due to a gun charge. He had some kind of tantrum and threw soup (at the coaches?) in the Cavs lockerroom which led to him being traded to Houston.
He's put up some good numbers while playing for Houston but they still seem ready to potentially move on with Amen who will eventually take his starting spot. He was also suspended by the Rockets for a behavior issue. I don't know if I would call him a headcase but he certainly seems to have a history of bad behavior. He doesn't check the boxes as far as being a high character lockerroom guy.