I have just downloaded the latest version of carbonite and the only difference seems to be a halo on my head.
It disappears when i do ALT-Z and when i enter Dalaran. It only appeared after i tried to update carbonite 3.1.
Also, I am unsure whether carbonite has updated as i had no agreements to agree to and no notification when i logged into WoW.
Update: when i fight it disappears only to reappear when i have killed the baddies.