1. Was everybody in the fireteam on the same step? 2. During the run in which you reached the final puzzle room was there any point at which your team experienced a full wipe after shooting the first crystal? (I cannot confirm whether this is correct but I have seen it suggested elsewhere that a team wipe will cause the game to forget all previously shot crystals, requiring you to start a fresh run) (΄◉◞౪◟◉｀)