My house batteries are separate from the coach battery, even though there is a battery disconnect for the house batteries I have an independent switch on the house batteries themselves.
I found a parasitic draw that kept the house batteries drained during storage. Even with everything, including the carbon monoxide detector off, there was still a slight drain. So...I completely isolated the house batteries with a simple switch and no longer have any issue. I have heard many different possible reasons, but I took the simple approach. Been told the coach disconnect switch itself takes power, heard diodes in the alternator drain power, heard so many possible reasons. So, like I said they are now completely disconnected and isolated during storage. Just my situation, the cheap switch did the trick and kept any feed back from happening. Electricity sometimes can be strange. Always on the look out for any avenue to travel. Sorry if this didn't answer you question, I tend to ramble at times