Umm… Also, I’m not sure the DoOnce is doing what you want it to.
What I would do is play the montage when not already chopping and then add a notification to the chop animation that indicates the swing is complete. Then when that event is triggered, I would change IsChopping to false so the montage can play again. The fact that it hit something has nothing to do with whether or not the swing is finished – I think that’s the basic problem in your logic.