Nothing new to report yet. New hotel booking using points was fine.

if my points did/do go negative, or weren’t available for the more recent previous stay, I was planning to transfer points from a cc.

the “play it safe” route, my preference is more the opposite, take the risk and see what happens (but also ask if others have had a similar experience to set expectations).

I’ll share back here if this ever gets resolved one way or another. As of now, checked out on 11/19, used points for reward on 11/19 at new hotel. My current balance will put me negative by a few thousand if the Austria hotel finds their mistake.