He was a lock because no kid with any sense that's serious about his career and likes being in South Florida would conceivably leave if the money was there.
Problem is this kid is not a culture fit and probably saw how serious and not goofy all of his team mates were going to be and said oh ok I'm not signing up for 3 years of torture cause these dudes are too mean and serious for me.
Kid probably wanted to be with a group that is more "fun" and goofy. For him that was the dorks at A&M. Remember 8&4 have recruited a huge string of low character 5 star busts. I have no doubt watching his commitment and some of his other videos that he wasn't going to work out here.
Also Lance said when breaking down his film that he lacked violence and didn't finish in the trenches only on the second level when he had a big size advantage. I'm sure given the tools Mario sees the kid and feels like he can mold him into something special. Kid just didn't think he needs that, maybe doesn't even want it. Kid could just want to collect his bag have a great four years at A&M and then become a florist or fashion designer