Yeah, I've been finding this out with the MPP LV6548 as well. I instead decided I will wire in a selector for the generator, and have one circuit go to the MPP AC input, and the other will be for a couple standalone 48v DC chargers, and will most likely only use the generator for the standalone chargers, since I am off-grid and only want to run on inverter power 100% of the time.
But the selector will just be there in a bind if I have an issue with the standalone chargers, such that in an emergency, I could put the MPP inverters into standby and use those onboard chargers to charge if needed.