Thanks for the confirmation. I believe Firefox isn’t ideal for Godot web games at least on itch, based on past experience. Would you be able to confirm if it happens on Chrome or Edge on your same setup?
After looking into it, it seems to be a common Firefox issue for Godot web builds, mouse behavior is not accurately captured when not in full screen. I believe if you play in full screen it should resolve itself. Apologies that there’s no other workaround.