i got a nasty surprise of this yesterday when I asked my travel agent husband to check some AY and AA combinations on SABRE that I was looking for to buy . The flights came up but the inventory was empty.
No notice from AY or anything, usually these things come up before it happens. Finnair agent CS was very vague about it... asking if he had not heard the news (???)
But she would not confirm that AY is no longer offered on SABRE. The codeshares with AA or BA still come up and can be booked.

A very strange way to handle things by AY, IMHO.