Cutting at own depth at end of project (Z misbehaving)

please help , my machine has its own mind. happend twice now , almost at the end of the project , the cutting depth changes to more than double to what i set it to and ruins everything. it works well till to a certian point then it cuts at its own depth.

Share your Easel file is possible.

ok please advise me how to do it.

I have shared the file
Thank you

Is your feed rate really 30,000 mm per minute? I think X-Carves no-load max is about 8000 to 8600. Even 3,000 might be a little fast although your depth of cut is not deep and I might work. I would probably start at about 2000 with a depth of about 1.2 and see what happens. If it cuts OK there (and it should) you can always bump the speed up during the cut.

Too fast of speed could be causing loss of steps.