Hi Jas,
Sorry about your trouble but I must say I was thrilled to see I'm not the only one with weird SurgeGuard behavior!
Mine started a little over a year ago and, like you indicate, it doesn't matter where I plug in and it also happens with the generator, that maybe one out of three times, the SG will count up to 128 secs then the screen will go blank. And of course there is no connection without that built-in SG working.
When I was at Phoenix this Spring, they tried to replicate the problem several times and of course it did not happen then. They really couldn't guess what was the problem. They gave me a dummy electrical box that I can connect all the SG wires to if I ever decide to take the SG out. I wanted this just in case the thing ever went totally bonkers and simply would not work. I think that's one of the downsides to a built-in unit. Unlike Progressive, SurgeGuard does not have a bypass switch. If it breaks, you can't get shore or generator power without somehow bypassing it.
At one point I called SG and they said that the unit will do this if there is a faulty ground or reverse polarity somewhere in the rig. In other words, it doesn't just react to the outside power source. It won't give an error code, though, unless the fault is from the outside power source. That's why the screen just goes blank.
After much trial and error, the only thing I have found that consistently works is to flip the breaker off for the converter/microwave whenever I hook up. After the SG's 128 sec countdown and approval of the power source, I then flip that breaker on and all is good.
Maybe something like that will help you get by for now, until you can find a more permanent solution. Please pass along to the rest of us what you discover, if anything!
Good luck!