It gets challenged, and somehow, someway they uphold the no-call. Rules expert pointed out that there were actually three instances of PI on that single play, yet the refs were too proud to overturn it. Still, they have managed to call every other ticky-tack thing imaginable. Ugh.
A pass interference that was so obvious that it looked almost intentional was somehow missed by the refs in this Baltimore/Houston game
The cya move to allow challenging penalties has been a complete farce. This is a classic example