There is a bug throughout the entire Ropalyst fight where if you fall off the map at certain times you will be stuck in a continual falling respawn loop where the screen goes black, it "resets" you, and you're stuck unable to do anything. This will also cause the player character to act as if it "respawned" on a flat surface, so movement is impossible. This can be reset with death or boss fight cutscenes, but it can also last until extraction, making the fight unplayable. I have gotten this every fight in a row because it's inevitable that you will fall off the platforms at some point. There doesn't seem to be a consistent trigger on location or moment, just falling off the platforms.