First off what a catch in the endzone. He can be so good sometimes it is scary. The problem is when he knows the play is not going to him he doesn't sell it. I blame this on old coaching.(Old habits are hard to break)
If it is a run play he should run his route as if it were coming to him. I seen him several times just trotting along and not selling it. When you do thiat the corners and safeties all come up and it spells disaster for your running game.