Chuck,
I assume you have Magnum Hybrid 4KW units.
First, a loose neutral is a very bad thing. The easiest way to see this is through a wide fluctuation between L1 and L2 voltage readings. But that doesn't sound like your problem.
Your current draw is HUGE! is that real? Read the inverter remotes assuming they were wired exactly like the Trace units.
Depending on how the inverters are configured you might see the remotes displaying load sharing. In this case they are adding inverted power to the shore supply. I set mine not to do this even though it's a beneficial feature. These inverters can pass 60A through them, just like the Trace units.
It seems like you can always overcome the problem by using the bypass switches. These bypass the loads without removing the charger function from the inverters. The only thing that should accomplish is allowing the inverters run cooler. Have you looked at the alarms through the Tech menu?
If your Vantare load shedding function doesn't work or is reacting too slow, you are looking for problems. The same with the air conditioners. If EasyStarts weren't installed, the inverters will most likely go into an over current condition when the ACs start. When I replaced my Trace units I rewired my AC distribution adding a transfer switch and inverter sub panel to only pass inverter supported loads through the inverter.
If your generator autostart uses the Magnum network module I wonder if it works. Few, including Magnum, doesn't get this right. The Magnum router is a must for everything to work correctly.