Faulty battery disconnect or latching relay?

[bm9201]

I just bought a new battery for my 2017 Jayco Melbourne and a couple days later the 12 volt lights in the kitchen area would not come on but the ones in the rear worked. I turned the disconnect on and off a few times but still had the same problem. When I turned the disconnect off and on the latching relay did not make any sound. About 20 minutes later all 12 volt circuits were off. When I turned off the disconnect the disconnect light remained on. About one hour later the disconnect light was off. I tried to start generator but it would not crank so I started the Mercedes engine and all 12 volt circuits started working and generator would start. When I turned the engine off all the 12 volt circuits remained in operation. I then turned the disconnect on and off several times and the latching relay worked. I am not connected to shore power and the battery connections are tight and battery is fully charged. I hope I'm using the correct term 'latching relay'. It's the part that makes two different clicking sounds when activated or deactivated.

Has anyone ever had a problem similar to this?