Blair, who overplayed the tackle, was SS. Not sure if they had switched roles to disguise something or what.
The prime mistake here was the coverage by Ballard. He was supposed to pick up Bushman and played it very poorly.
Don’t get me wrong, Bushman is a very good TE and will likely play in the NFL. But that video is more a display of a missed assignment than it is a spectacular play by Bushman. That was as easy as it gets for BYU. If Utah plays defense like that, they are in real trouble.