It could be a lot of things. Who knows.
That said, Texas would be a better defensive football team with him as a DT than it would be without him. And for that reason, I think UT continues to pursue.
Kids are often immature at this stage of their life. Kids grow out of that, especially when under great leadership. His antics don't bother me, though I get tired of hearing about them.
I think there's still some bitterness there with regard to aggy. They are his fall back plan because they'll take him back no matter what (as they should). So Auburn, IMO, is there as a result of "what other possibilities are there for me?" He's said he wants to play in the SEC so that's an option that doesn't require him to be aggy.
It's been my experience in situations where a kid suddenly seems angry at a staff, a phone call usually clears this stuff up – or – the staff is so turned off they go the other way. I'm guessing some phone calls are being made.
I think Mack ends up visiting Texas. Yet another visit to dead-dog town will teach him nothing he doesn't already know. He at least needs to see what he's saying no to.