"Rule 8, Section 1, Article 3, Item 1 of the NFL Rule Book (page 51) states that 'if a player goes to the ground in the act of catching a pass (with or without contact with an opponent), he must maintain control of the ball after he touches the ground, whether in the field of play or in the end zone. If he loses control of the ball, and the ball touches the ground before he regains control, the pass is incomplete. If he regains control prior to the ball touching the ground, the pass is complete."'
Again,he wasn't "going to the ground in the act of catching a pass".
It was caught two steps before he was drug down.