Maybe used Aspire to generate separate gcode files for each circle? There's quite a small stepover as well, from what I can see, which is probably not needed for cutting this material. Not how I would have done it, but not the issue here, I think. It does take a while to get the hang of all the different settings once you start using any CAM package. I still favour mechanical overload causing something to slip, having had exactly this problem setting up my own new machine a week or two back