We were on turn 20ish, and FlyinWren requested an undo, as they had wanted to call teacher and played a caravan guard by mistake. I OK'd the Undo, and then nothing happened. They tried again, and nothing happened. Figuring the game was stuck or something, I also requested an Undo to see what happened. Somehow, this took us back multiple turns, back to turn 13. it was really disorienting, as we had emptied two piles from turn 13 to whatever turn we were on. Kept going and things played out alright, but there was definitely some bug going on with the undo function.