Obviously his demeanor and work rate are below par. I don't understand why. Maybe he has issues in his personal life? Who knows.
I have problems with his decision making. He dribbles into blind alleys, shoots when he should pass, he slows our play down with his dribbles, doesn',t release the ball quickly enough, claims freekicks.
But of course, his biggest problem is his work rate: not tracking back and jogging around. Just look at Garnacho yesterday. Not everything worked out for him, but at least he worked his socks off.
I would start Garnacho against Bournemouth, sub him off around 60 min for Rashford and let Garnacho start against Bayern.