Did this happen on the first carve after powering up? My machines did this a couple of times in the past so for the first carve after powering up, I now run a test cut with the Z axis raised up so that I can hit the stop button should gold mining takes place and before the cutter can ruin the material blank. I then set the Z height properly and run the program. I have never had the problem occur after the first cut. Check my other posts about recommended powering up procedures.
Let me know if you get another solution.
Ron.