I believe it is bugged.
I just got it on my alliance toon in 5 kills. Other alliance report it dropping, however horde do not. So I would wait it out :/
Alot of NPC ID's are messed up aswell. I had the Goldtooth necklace drop of some random wandering Kobold aswell. The new SM Whitemane and the Old Scholomance bosses also retain their drops from before the updates. I hope i haven't induced false hope, but i really do hope they fix the ID issue.