Its not cutting of, its just playing way too fast. You dont have the animationframerate set in the skin.ini. If its not defined osu will use allframes/second as the fps instead. So rn its playing all frames every second. So you need to set that in the skin.ini. This will however also affect other animations like play skip and followpoints. You need to set the menu-back to the fps you want and then you need to add more frames to the other animations to make them fit the new framerate