That does seem to be what happened although it's not totally obvious to me why. I guess there aren't many (maybe aren't any?) data points on what an OWV points booking would have cost in the old SPG program but I assume it was more than a 6.667K Starpoints buy-up, if it was available at all. So it's not like the existence of the 80K rate was some sort of holdover from old SPG.

It's also possible that the 80K was effectively just an error rate, especially since the St. Regis Maldives had a similar one that got squashed quickly, though if that's the case it's surprising that it remained bookable for so long. I guess good things don't last forever though.

Or, maybe it will come back at some point; I haven't yet come across any SPG hotels that offer ugpraded room categories for booking with points online yet, even at hotels that used to be good about offering upgraded room points bookings if you called (like the Great Northern in London for example, though I haven't had reason to call and see if upgraded rooms on points are still available by phone at that property). Many Marriott properties offer some upgraded room options on points as well, so perhaps Marriott has just disabled those for some time while getting systems issues sorted out, and hopefully they'll come back at some point in the future. Though who knows if that will be before December 31 or not.