The only up-to-date commonly used randomizers with meaningfully common impossible states I've seen are in Fire Emblem, which is difficult enough to begin with that unlucky changes to earlygame units and bosses can create a (near) unwinnable fight. You also have to deal with alternate loss conditions such as NPCs that cause game over on death and change to a class that is frailer than default or unable to move on the terrain type they spawn on.