There is a bug in the Arts Battle, and a notice has been posted on X about the release of a fixed version, Ver. 4.8.12, so I would like to ask you to please wait a little while until Ver. 4.8.12 is released.
Is there a bug in the mod program? When playing the main battle, the modified items will only be reflected on the leftmost character, and the other characters will be weakened, and the monster on the far right will receive the modified attack bonus
