From what have been reported in the past few weeks, it seems IF you already have a CONFIRMED booking, when you tried to do a change online, with the availability shown of course, you got the error message and the reservation disappeared from AS but showed as Waitlisted on CX side. Then it takes a few days the error / glitch were corrected either thru AS desk working with CX desk or whatever - there are 2 or 3 reports of final successes.

HOWEVER, IF you tried to book a NEW reservation, it is not possible to go beyond the error message. If you got an incompetent agent (read, had no clue on how things work) who tried to push thru the booking, you ended up having a mess - CX showed Waitlisted, AS did not recognize your AS PNR, tickets never issued. You then have to call to get the miles / $ refunded back.

I saw some newly released seats in Nov that were not there before - but none bookable using multi-city US-HKG-AUS. Both the seats on the US-HKG and HKG-AUS were in November, hence not there before. Yet, they are still all phantom.