That was obvious in real time, and even moreso in the replay. Then it went of the BYU player's leg into backcourt. It was clearly a badly-missed call, and there's no justification for it after the fact. If you want to suggest the refs thought something else happened, therefore they just saw it wrong, that's possible. But to argue there's a possible justification for it from the rules after seeing the replay is clearly mistaken.

Add to that, the Pac-12 homer announcers arguing it was the right call after seeing the replay a few times is just laughable. Nope, clearly, indisputably a bad call.