OK, it's happened enough times now that I can confidently say Texas' DBs are having trouble handling switch releases. It's an important thing to watch going forward.
I'm pretty sure this is Bonney's cover bust. It doesn't make sense for Hill to chase No. 1 underneath.
On a side note, I don't know what Davante Davis is doing up there on the top. I've seen him do this a few times, including against TCU when Josh Doctson caught an easy pass down the sideline. He doesn't have safety help, but it's like he thinks if the quarterback doesn't look to his side he doesn't have to cover.
And a last thing. I saw some people complaining on Twitter about Texas "not covering the No. 3 receiver" in the second half. It started I think because the announcers stupidly highlighted a look like this and said Texas was playing 2-on-3. I hope this diagram convinces you that that wasn't true.