IMO, what you are experiencing is a generator that is too small for the loads that you are imposing on it.
As others have mentioned, there are potentially numerous electrical loads which may automatically duty cycle through your electrical system without your knowledge.
Based on the ambient temperature, humidity, elevation, barometric pressure, fuel (gasoline or propane) your generator may not be able to generate full rated power. IMO, generally, when your genny keeps kicking off (due to overload) that's what it is trying to tell you.
IMO you need to do some data logging so that you KNOW what the loads are. Don't guess.
Chum lee