Conquest of the Horde

I opened up my bags, and prepared to hearth to find my Hearthstone unuseable and in this format.
Hearthstone
Soulbound
Unique
"1"

I don't know what happened, but it's annoying me, and if anyone can give me some advice on how to fix it I'd appreciate it.

Try destroying it and buying a new one perhaps?

I forgot to mention that I tried that, and it didn't work. It just gave me another bugged one.

Have you tried the most important thing? ie, purging your cache?