so my friend and i have rise of iron each, and he came over to my house to play it (because that's what we do). he finished the Gjallerhorn quest on my console, and now he can't use the iron gjallerhorn on his console. he redid the missions and still wasn't able to use the Iron Gjallerhorn. what's the issue at hand here, Bungie? *UPDATE* the problem for my friend was that none of the DLC was installed... which is weird considering he's been able to play it since i bought it for him.