Z-axis lowered after pausing and resuming

Pausing and restarting a long sign carving job seems to have lowered the z-axis by about 1cm, which ended up ruining the piece. It was about 3 hours in, and had about another hour to go.

I double checked the file simulation both on my computer and inspected the preview on linuxcnc, and nothing seemed to indicate that it would drop the z-axis. Is this a known issue?

The program was generated using Vectric Aspire 8.5. This is the setup for our machine: github.com/quarklark/GSS-CNC/wiki

Any suggestions on how to further debug it?

How did you pause the machine? Was the machine turned off or axis disabled at any time while stopped?

I just clicked the "Pause" button in the top of the GUI. It was only paused for < 2 min, and I didn't change anything about the machine.

It is possible that when the machine is paused the drive is disabled and the Z dropped down. Though pause should not disable the drives.