That was another example of why this "scoring plays are automatically reviewed" rule doesn't work properly. That WAS a scoring play, one official even called it as such. They eventually ruled it wasn't... but it was. Because they ruled it wasn't, no review, and it turned out there was no way to challenge the error. Rick Campbell tried by challenging something else on the same play, but it didn't work.
Had it been looked at, it would have been overturned quickly, as the replay was very clear.
It seems weird that you can't challenge "the guy didn't step out of bounds" but you can challenge PI.