Intermittent 12v electrical issue

Running the camper on generator power this weekend and cut the generator off to find I had no 12v power anywhere in the camper. Checked all fuses and pulled the fuse panel with zero 12v power coming in. Went outside and battery tested fine, replaced the 30 amp blade fuse just for fun and it tested fine. Got to the junction box and had power there as well. Finally gave up after an hour of taking things apart and figured I’d bring the camper home to mess with it more. Fired the generator up again for some coffee, then cut it off and what do you know…..12v power everywhere. Well problem solved I guess….no. Turn off the generator and go to unhook the battery since I won’t be out for a couple weeks. Just for fun hooked it back up. Nothing again. Shook the wires and it came on. Did it again and lights are back on. My first thought was the connectors but that doesn’t make sense from the original problem where I had power 4 feet away at the junction. Any ideas on what to check or replace?

One other thing I forgot to mention. I don’t recall the green light on my fuse board ever being on this weekend. Not sure if that is related but worth mentioning.