You need to determine what the house battery voltage is. To do this you will need to turn off both inverters, shore power, the generator, and the engine. Absent all charging and not allowing the inverters to drain the batteries, you will need to read the battery bank voltage. You can read the DC voltage at the inverter remotes or the DC cables attached to the inverters, if you have a voltmeter. You can also measure it at the equalizer or battery bank, if either are accessible.

Reading the voltage 30 minutes after shutting everything off should be enough time to read the voltage affects of a bad battery. You should expect a voltage of at least 25V.

I'm not sure what Liberty used those contactors (transfer switches) for. I suspect to prevent power to the coach until they check it. Liberty doesn't generally provide electrical drawings, so there's little chance you have drawings. I suspect the contactor energizing coil is 24V and your batteries are to blame.

If the DC voltage was well below 25V, you can try to eliminate a bad battery, if you can't get them replaced soon. Some battery installations are too hard to access to attempt to eliminate a bad battery, unless you really have to.

The DC switches have to stay on. The 24V house switches connect the batteries to the inverters. If there are no switches labeled inverter by-pass or similar, you don't have them.

You should turn down your inverter's charge current if you have a bad battery. This will help reduce the possibility of charger damage.