Thanks for letting me know!
It is a common error, but is usually fixed by allowing itch.io to have experimental SharedArrayBuffer support, and it seems to work for me and other people. So i want to ask, what browser are you on? Did you modify its settings?
Additionally, jam games are locked during voting and if i make an alt game just to upload a downloadable build during the voting period, this will be a problem as i have already made just about enough changes to the game for it to be different. So unfortunately what is uploaded is uploaded… I’ll give you a Windows build after voting ends!