Dodgeyou
Dodgefathered
From what ive seen, all zones that got changed with Cata are now undiscovered areas if you had discovered them before. If your toon didnt have XP off when u logged him out, then, as soon as you logged onto him in the new Org he discovered Org again and dinged. Its unfortunate, but not an isolated incident. Have been several people had that happen. If he was XP was capped when u parked him tho, then, its Blizzards glitch and I see no reason why they wouldnt fix it other then they are just stubborn about deleveling a toon. Its a crap shoot. Good luck.