He is just chaotic. Very inconsistent with his decisions on and off the ball. Nobody knows what he will do including himself, and it can mean he scores, it can also make him a very hard player to play with.
Good player and has some big strengths but I wouldn't start him in these kind of high level games because it can go seriously wrong. He is tactically inconsistent and its hard to rely on him in games where some nuance is needed, sometimes he needs to slow down the game but he can only play on one setting.