[DonRotolo]

...and if it is losing zero instantly some time during run, then it is likely a bad connection, electrical interference, or (depending on how zero is set) something accidentally resetting the zero. Soyy, I'm not familiar with V-Carve

Unplug and reconnect every connector and terminal, regardless of where.

has the machine been moved recently, or any new machines (or anything electrical/electronic) in the area? Like a welder?

When you run it, are any other machines in the shop in use?