Have they changed the rule on players running out of bounds on kick/punt returns? As I remember it, it used to be if you were a gunner and ran out of bounds, you could not be the first person to touch either the ball or the returner. I even remember a play where someone ran out of bounds, and was the first person to touch the ball - and only to down it - and a penalty was called.
Because when they showed the side replay on the William's muff, you can see the Giant player run out of bounds, then come back in - and he was the one to recover the muff. So unless the rule has been changed, that should have been an illegal touch and a Giants' penalty.