FE6 Demonstone fix?


Does anyone know why this happens when you give Idunn her personal weapon?
I have already seen people fight her while she uses it and it worked fine then.
I know it has something to do with the game calling some hidden ASM stuff or something like that because that is her programmed battleanimation, but how can I change it so that her Dark Breath-animation is used for both weapons?(Since I want her to spawn with the stone in hardmode,but the breath in normal)