A final question.......
Has anyone ever heard of a situation such as the following?
Suppose you have a small device plugged into the DC outlet on the generator......
Is there any known circuitry inside a portable Inverter Generator that might sense that something is connected to the 12vDC port and then limit the output to the AC outlets?
I did initially have a small 12vDC device plugged in when I was having the issue in the OP. But I have no idea if that could cause the generator to reduce it's available output to the AC outlets.
I've never dug into that, but I've also never needed to use the 12V output from my generators, either. Don't know whether it would limit anything based on DC usage. But even if it did, the DC wouldn't use much of your capacity. Even 10A of DC (the most my cigarette lighter outlet can supply) would still only be 120W.
From units I've had, that DC output is typically unregulated voltage, and is really intended just for charging batteries, not so much for running cigarette-lighter style loads.