I’ve had this happen twice on the same job (a tool holder for my collection of endmills) and hasn’t happened in the same spot. It seems that the Z axis is not coming all the way up before moving to drill the next hole.
It does occur pretty far into the job, so I’m wondering if it’s just the z-axis driver getting warm and deciding it doesn’t want to do any work for a step or two and then kicking back in? What’s interesting is that it does successfully drill the next few holes, so the Z does kick back in and runs smoothly, it’s just a little low in the work piece so leaves some pretty trails in it…
Electronics and vitamins are all from Vicious1, I printed my own parts. EstlCAM for generating G-code, printing from SD card.