Well, if Roberts has flipped and is suddenly going to decide that he was wrong that "deportations" under the AEA can only be challenged via individualized habeas actions, that'd be the quickest "we fucked up" in SCOTUS history. They usually wait at least ten years before even implicitly admitting they fucked up.
Since this is an administrative stay, my guess is Roberts wants a little more time to figure out how he can better define the notice requirements they established under J.G.G. two weeks ago. But that was when he fucked up and, short of openly admitting that order was wrong and Boasberg's TRO was appropriate, I don't see how they can fix the problem Roberts walked them into. Boasberg's TRO was clearly necessary and that challenge under the APA should've been allowed to proceed. But Roberts wanted to give Trump enough wriggle room to mass deport people without it looking like Trump was clearly violating both court orders and human rights (knowing that even with notice, most of the detainees wouldn't be able to effectively file habeas actions), and lacked the foresight to understand how the administration would respond to the nice clever little loophole Roberts had given them. So he's basically back where he started, but now trying to figure out a way around his own ruling from two weeks ago that rewrote a whole lot of law on the fly, wholly based on political considerations and without putting any real thought into the legal implications.
Maybe Roberts actually is just genuinely a dumbass.