Thank you so much Nels for your insight. I checked all three devices and you are right. The mouse and throttle each had settings similar to the ones I have in the joystick.
I went through quickly and deleted the duplicates and made a short flight. The problem did not recur.
I will spend more time tomorrow on this issue, but I believe you have hit on the solution.
Too bad MSFS does not have a way to identify duplicate settings between devices or does it?
Again, thank you.