Houhou: Sword Style Bug with Ougi Celestial Sync

Playing Sword Style Houhou, i noticed a glitch kept happening during party. I was able to replicate it and found the condition to trigger this glitch. A targetable staff skill has to be used during the animation of Celestial Sync. It does hit twice when it activates. and it looks like it can activate during the windup animation, in addition to after the slice animation. In my testing, you cannot infinite chain it, and will only happen once per Ougi cast.