Just heard from Alliance:
Good morning.
Thank you for reaching out.
For your unit and the open ground statement I would want a couple things checked out.
Check the connection at the transfer switch please. With all power off I would check the lugs on the switch. Make sure they are all tight.
Most Generators will show open ground since the unit is not grounded to the earth. All my generators show open ground when I work on my units.
On inverter power same concept. The inverter is grounded in the unit but still reads off the coach. There is no grounded lug to earth unitll shore power is plugged in.
I will check the transfer switch. Thanks.