Originally Posted by Dutchrudder
There is maybe a split second between the time the ball is touched and when Keuchly actually wraps up Gronk. Yes there was some contact there and it would normally be a PI, BUT the pass is undercut about 7 yards in front of them. Here's a gif of the play for reference:
When that happens, you employ this rule from your link:
Gronk was too far away from where the pass was intercepted to make a play on the ball or even the player for that matter. Therefore it is an uncatchable ball, and the flag gets picked up.
To me it looks like the interferance starts when he tries to make his cut back to the ball. He can't get to it because he is getting pushed back and then gets a big friendly hug from the defender.