Holy moly the ref crew just royally screwed up. Illinois tried to change defenses and had about 14 people on the field, they threw a flag but then took about 5-6 minutes to discuss, then pick up the flag and the head ref didn't turn his mic on to explain the call so nobody knows what they decided.
What I think happened was the refs should have stood over the ball because IU changed personnel and Illinois should have been given time to switch players but the ref didn't and let IU snap it. And then they talked about it and realized they screwed up.