His explanation sums it up. To abridge it even more, the problem here is that no one is 100% sure who actually has jurisdiction (the ability to decide anything) on the case right now; Judge Chupp, or the Appellate Court. There is a 99% chance that Judge Chupp still has jurisdiction and can proceed with his stuff, so the new defense attorney can fix this by dropping his appeal, and then appealing again (properly) after Chupp's final order. There is a 1% chance that the appellate court now has jurisdiction of the case and Chupp can't do anything, even if the Appellate Court is going to say "you did this too early" and kick it back to the lower court to Chupp. A court cannot make decisions directly affecting a case if it never had jurisdiction in the first place.
The catch is that in that 1% scenario, if the defense drops the appeal now, you typically can't get two bites at the apple (making corrections to a filed motion is one thing, but if you flat out drop/withdraw/etc your valid appeal, most courts will not let you re-file). On the other hand, if Chupp proceeds and the Appellate Court later tells him "sorry we had jurisdiction for these few weeks" and kicks it back down, Chupp not only has to redo everything after the appeal was filed because he technically never had the power to do anything once that appeal was filed, but guess who's going to knock on Vig's door for even more fees for having to deal with this?
It's one of those situations where local court rules and statutes probably haven't accounted for an attorney doing something really, really dumb