V-Carving with Aspire results in many deep plunges with a v-bit, and depending on flex in your spoil board, speed of your spindle, sharpness of your bit, may be slipping the bit/router/clamp up when it can’t complete a deep cut. Loosing steps when trying to go down. The stepper thinks it has made the cut, but now Z-=0 is just a little higher. Etc…
4D