Could improper earth of welding machines cause VFD damage?

If the cables of a welding device of reasonable capacity are in close proximity to supply, load or control cables of a VFD, it is possible for cross talk from the welder to interfere with the correct operation of the drive. Proper earthing and shielding requirement should be adhered to to avoid damage. I would ensure that supply and load filters are fitted to the VFD and check for correct earthing on the welding device

Make certain that vfd source power, load power and control cables are separated and make certain that the welder power cables are distanced as long as possible from the vfd cables. All cables routed in steel conduit. The supply source should be at lease 10 times the full load value. Make certain all grounds use common point and the utility neutral is bonded.