Z-axis travel goes too deep

Hello everyone

I have an M1000 Stepcraft with a strange problem.
The problem is that when I run the G-code through the WinPC-NC USB the spindle goes too deep into the table.
I'm using Fusion360 to for CAM and I've attached the NC code.

When I zero the work piece I bring the tool till it touches the table slightly and zero the Z-coordinate of the work piece. But after I run the NC code it goes too deep into the table. And when I jog the spindle down the table surface becomes a positive number and not zero as I zeroed it before running the code.

Not sure what's the problem can you help out with it?

Thanks