When I got my 2016 RAM and went to have the camper put on, they checked to see if the RAM had and issolater.
Nope, so I had them put one in.
Otherwise, what happens when you pull the power cord from truck to camper... maybe it defaults to the Truck, dunno, but I would think if camper wasn't connected to the truck during that time, it might go to the camper batteries..
Just thinking out loud here... also, just in case, an inverter will draw power if on, might check that for power loss...
Hope that helps a little...