I also discovered a much bigger bug: The Infernal Strike event will stay applied forever even after leaving the floor it was triggered on. I tried to use a Summon Knight Scroll and the Infernal Strike message appeared, even though I had no events triggered on this floor.
Quitting and reloading the game doesn't remove it, but shutting down the game, restarting it and reloading the save file seems to be able to remove it. I could cast the scroll once again.
