I use the free version of Fusion and find it can do funny things. Once it decided to cut in multiple depths and the machine time should have been something like 20 minutes turn into 4 hours. The weird thing was I was just doing a simple pocket and was experimenting with how much material to leave. I had just made the same cut and decided to remove an extra .020" so the cut time should have been the same. I even had Fusion up on my laptop and was just editing and resaving the pocket cut so I didn’t change anything else.