Second time I've seen this... Settings say booted players go AI, but then a booted teammate disappeared as if the setting was "no AI"
That ^ is actually incorrect. What really happen is that a player got booted then turned into AI. Then the AI got booted the same turn. (You can see this in the history btw). This can occur if the server is having issues with making AI orders or it times out or something (should not happen but in rare circumstances can) .
Turn 1, player Avid was booted twice! [manually by Darius, and not by you according to the order list] once as human and once as AI.
Turn 2 your other teammate was booted once by you.
Normally, the AI is committing super-fast so you simply don't have time to boot it. Why that failed here I don't know, but one possible explanation is a server hiccup combined with rapid manual boot.
EDIT: Programming forum is not for bugs btw. Also, this is not a new thing, just (super) rare as I said.
Edited 2/12/2019 22:03:34