Playing in CotC today.
My pw: Oko.
Opponent: Oko.
I cast Turntimber, and it summoned out a Feasting Troll King on my opponent’s side of the board.
This was early in the game. His Oko did have a Fey Treat support on the board (Whenever a Food Token you control is destroyed or loses shield, fetch the first card from your opponent’s library.)
I don’t know why that would somehow interrupt and steal my creature, but it’s the only theory I can come up with. I’ve used Turntimber in other games and not had this problem.