It's a good question. I don't know if competing during a red shirt year counts as a competition for the above exception but I know regular redshirts do not have to be tied to a specific team. In general, you have 5 years to compete 4 years.
If you haven't been on scholarship for 2 years (because you weren't in school) it makes sense you wouldn't be tied to your original institution.
The other question would be does Gable need to be on scholarship to compete and, if not, is that other loophole? If he is going to get NIL, it could cover the cost of the scholarship, you would think the rules wouldn't prevent a "walk-on" from competing as strictly as scholarship athletes. And presumably he wasn't on scholarship at Minnesota the previous year (2 years?).