I see what's happening. So some recent changes allowed 3rd party skin developers to make their own mobile skins.
What you are actually seeing is the Vector skin minus scripts and styles (as none of the assets have been checked on mobile). (e.g. the Vector skin in target=mobile mode)
This should probably honour that the home page is a blacklisted page and apparently is always supposed to show in the Vector skin.
This would be a great opportunity to optimise that page for mobile and lead by example ;-)