Well I may have spoken too soon, as it seems that more strange things are happening.
Trying to fly PKX-LHR mid-August 2024 using AA mile redemption on aa.com
- Up until 10/31 (Tuesday), Etihad flights through AUH were abundant for days/weeks in either direction ... so I booked one of those.
- Yesterday on 11/1 (Wednesday), those were all gone, and a few random dates with BA showed up
- Today on 11/2 (Thursday), only thing showing up are a few dates with Qatar flights through DOH
Glad I learned my lesson the first time to not hesitate, but that still doesn't help me with some non-Codeshare BA flights I'm looking to book later in August. Guess I'll just keep trying.