Dunno if this is the right spot to report this, but I think I found an alchemy issue. Using the pyramid three ritual with 2 copper arms, a copper left leg, and an iron body acted as if all the arms were also iron, giving both the Iron<>Iron buff and the Union of M&V bonus. It also said there was a transmutation when one didn't happen.
EDIT: This only happens when the right left is stone and the head is Marrow