I played a Procession on a scheme which played my scheme twice and trashed it.
I didn't play any other actions that turn but after buying a card I was not prompted to topdeck any cards as expected and I was unable to end my turn.
I assumed it might be an issue with scheme's affect triggering from the trash or the fact that I had played scheme twice but only had one action still in play.
So I tested the same interaction again in a bot game and had the same issue. I also tried it with kings court + scheme.
I played KC + scheme so I had played scheme 3 times but only had 2 action cards in play. I could buy a card but then the game froze.
Game# 3750251
Was the bot game that demonstrated the KC part of the issue.
It's a known (or at least documented) problem, see: forum.shuffleit.nl/index.php?topic=1480
It seems we agree the root cause is more scheme effects than actions cards to apply them to.
Just had the same problem.
Also, note that it may not have gotten attention of devs, as it isn't part of the known card issues post yet.