I've played MyCareer mode, LeBron Path to Greatness, and an Association with my roommate where he player-locks on the center and I do not player-lock at all. In MyCareer, the issue exists. In the LeBron mode, I've had no issue most of the time, except for the one game I attempted to player-lock on LeBron (shocker). And in the Association, I've had no trouble, but my roommate has the same issue while he's player locked on the center (or any other position for that matter). For this reason I think the issue has something to do with the player-lock feature and the way it affects the controls.
P.S. I tried changing the Auto Shot Contest settings in the My Controller menu, but that didn't seem to make any difference at all. Don't know why I thought it would help, but hell, I gave it a shot