The backpiece itself is account bound. The grenth backpack was supposed to be account bound as well but there was a bug so people could sell them on the tp before it was patched.
If you mean the Recipe: Light of Dwayna, then yes, it is bugged out.
The recipe does not show up in the TP if you try to search for it.
The screen shot there shows that people who have the item have put them up on the trading post to sell as well as placed buy orders.
So the issue is that while the recipe is not account bound anymore, its not registering properly on the trading post.
