I've noticed a bug that's popped up lately that involves items with a different price from the main item. The higher priced item (in this case, a soundtrack) gets unchecked and loses its price when the regular priced item (in this case, the game) gets reuploaded (replacing the original zip). I then have to reset the price of the soundtrack every time I update the game.

This may also happen when any file is uploaded to a project page, but I haven't tested this yet.