Removing Bar.BackgroundEmpty="progress.empty" from my styles made the Bar.Background empty correctly.. However now my gauges are now transparent when empty.. I'm still hoping for confirmation that this is a bug and will be fixed..
I think I will bug it ingame and hope they give it a higher priority than /loadui so it's fixed sometime before the next 8 live updates or six/seven months!! (Throw an intern on it or something)
Sorry for the little rant