In your RV Custom Products Battery Control Center (BCC) is a silver isolator relay. It is probably the reason your chassis battery is not charging when on generator or shore power. It will also keep your house batteries from charging when the engine is running. That relay has a high failure rate. When replacing, make sure you purchase a "Continues Duty" relay. The 2 battery bank disconnect relays are also in the BCC. They are in a black plastic housing.
The cigarette lighter and propane detector are intentionally left connected, by Fleetwood, when the batteries are disconnected.
When you push the AUX battery cut off switch to off, the house batteries should be disconnected.
Your propane detector is powered from both battery banks.
Richard
95 Bounder