Generator

Last week we were at Lake Shasta and one early morning I was awakened with my generator starting on its own. We were plugged into the 50 amp campground power and I do not have automatic start on the generator. The generator is an Onan 7.5 diesel. I got up and shut it off and I did notice that my microwave was flashing and I reset it. I did have my Hughes Autoformer plugged in but without auto start I don't see that would make a difference. I started the generator today at home and run it a couple of hours with the front air conditioner on and it run fine, it did seem too crank a little longer but otherwise good. I did service it in February with oil change and new filters. I have had the motorhome since new and the starting issue has never happened before. Any ideas what could have caused this starting by itself?