House Batteries are fully charged but acts like they are not

I have a 2010 Class A Georgetown ForestRiver. Electrical works fine when plugged into shore power. When I took it off shorepower, generator would not start, steps would not come in, interior lights would not come on and jacks would not come up. Thinking the house batteries may be dead, I took the house batteries out and had the checked. Was told they were fully charged and was told everything was fine with the batteries. I put the house batteries back in and left the RV running for about 20 minutes. The Generator started and got the jacks up. Left generator running while I drove the RV for about an hour. When I stopped, I turned the general off, and just to see what happens I turned the interior lights on and they stayed on for about 5 minutes and then went off. Everything is acting like the house batteries are dead, but I just can't figure out why that is and what is wrong. The chassis battery starts the Rig up just fine, and not sure if that would have anything to do with it anyway.

Anyone have any suggestions on what could be my problem and how to fix? Thank you in advance