I'm still staying partial to the theory that Temple told him they couldn't get him eligibility. It was noted locally in Temple circles as a surprise that he wasn't out there for the practice the Saturday before he entered the portal. The Griz also have a recent history of working the system to get some waivers that were considered a long shot. (Walker was even moved back home to Nebraska when he found out he had another year). Temple's staff may be FBS, but they are probably less funded and is definitely less experienced than our athletic/coaching staff. As with any governing body, there are a litany of by-laws, rules, procedures, and best practices that a talented person can find loopholes in. My impression is that we have a strong understanding around that right now.
Everything out of the reporting I read sounded like he was competing well for the starting spot. He ripped off a 40 yard TD run the day or so before he left the team, and it sounds like his passing was a very pleasant surprise. It seems like a very sudden change. It is my strong suspicion that people on their athletic staff grabbed him and said "hey, we don't know what the people from the U of Montana told you, but we can't figure out a way to get you a waiver," simply because they don't have the ability to get him one that our staff knew they could finagle.