Not once do I see his knee hit the ground, and the whistle being blown before the play was really dead is part of the problem. It is what it is, the Irish got away with a big one.
And saying the Pitt call was iffy is ridiculous. There is no way, in any sense, that that is pass interference. Literally no way. I'll give "iffy" on the Stanford call, but the Pitt call was a clear blown call.