Black Abyssal Weapon Exchange

I got my black abyssal weapon and upgraded it into "yellow grade" black abyssal weapon using the black cast iron that was given at the end of mediah main quest, I was planning to reroll it into other class and I cant process heat the yellow grade weapon and black alloy to get the box.

I think I have to revert the "Charm of the Black Tale" back to this weapon to be able to process it

 

Yeah this seems very much like a bug to me, and therefore you should post it in the bugs section, that way it will get looked at by the Developers and solved.