Gronk was flagged. It was just offset by Hyde's penalty on the same play.
Which is really stupid. One team commits two personal fouls, but gets left off the hook because the other team committed one.
Screw that. In that situation, Amendola's and Hyde's penalties should have offset and then Gronks should have been enforced. I mean, in the end it didn't matter because of Jerry Hughes, but at least we would have ended up in the same spot.