Thanks for explanation, maybe I will start pestering Working Title.   I dont use the GTN750 at all, prefer the older instruments, but nevertheless, it still happens too often.   Great pity to have relatively expensive payware and get these problems.
Actually, I also see that the aircraft dont always save their current state on shutdown.  I usually go back to cold and dark, with G530/430 chosen.  But on restart, the GTN750 bezel is present, will see if I get a plan to load when aircraft loads G530, from cold.
Is it possible to force a particular loading configuration in the aircraft configuration file??