[RMVX ACE] PROBLEM WITH CUSTOM ANIMATION/SE

I've made a custom battle Animation that plays a custom SE for the final boss of my game. I tested it in the Battle Test option and when the boss uses a specific skill that animation along with the SE plays without a problem. But when I normally play through my game and reach the boss the SE of the animation gets somehow bugged and plays twice or thrice. Anyone knows what could cause that bug? I thought maybe the boss had Action times+ enabled and the double move would glitch the animation but it doesn't have it enabled. Any help would be greatly appreciated.