I tried replaying the game from the start, but the error happened again at the same spot. It also happened when I selected 'Continue' in the main menu.
I can confirm that's never been a file present in my project haha. I suspect something strange is going on related to how web deployments manage saves, probably a game ID issue but it's beyond me... your most recent project is calling files used in mine, for example. Maybe try playing in incognito mode, that seems to avoid file conflicts on my end