The batteries are very new.... all three with date codes of 5/14.
The two house batteries are liquid and the starting battery is an AGM Optima Red top (a good battery). I will take it back to see if I can get any support from the retailer. BUT, I wasn't the owner at the time of purchase so they may shoot me down without providing a receipt.
The house batteries were VERY low on water... if not totally dry when I discovered the problem. RV dealer thinks the Optima started the problem by way of a bad cell.
I plan to replace that first and then go from there. I don't boon dock so that isn't a problem for me. But I also keep the RV in a storage lot with no access to be able to do a trickle charge. So that is why I went the route of a cutoff switch to begin with.
Many thanks for the continued support and advice.