The “changeable parchment” card interrupts and crashes the game. I ended up at the last “cursed wood” boss, I had the upper hand and I lose every time this card pops up. The battlefield scenery and parameters are active but the characters and cards are frozen. I have a medium level so I will take time to join this boss, especially if I have to avoid this card
Immediately try a forced quit and restart.
This has been reported multiple times and is a Known Issue: