they are not invisible buildings... like someone else already pointed out, those th10s haven't even finished their war bases, the "unspawnable" areas or "shadows" (w/e u wanna call them) will be spawnable once the war starts.
war matchmaking takes whatever you have into consideration, it has nothing to do with layout. so those comments saying "matchmaking uses farming bases" do not make sense at all, cuz the logic in itself is completely flawed.