Okay so, yeah, if you play through long sections that have scripted animations and freeze, then replay them by holding left click without letting go, you can reproduce a “glitch” whereby a sprite can appear in two places at once, a desync. Any input other than already having been previously already holding down left click causes a game freeze at this point. I think it’s an engine bug. Not a bug in this game.
Although being able to save halfway through super long segments would make the problem almost entirely vanish. Also someone else feel free to confirm this observation, I’m not replaying the sleepover for a 12th time 