UPDATE: SUCCESS!
Gents,
After painstakingly binding each individual key, one at a time, to various buttons, switches and levers on my Warthog, and testing everything each step along the way, I now have a very flyable Mosquito!
It would seem that there are some actuators on my equipment (Thrustmaster) that can be problematic in some applications. One was causing a "stuck key" event when paired with a modal (UMD) key, and another one seemed to be causing time compression to kick in inadvertently on a RCTL z command (still not 100% sure how that was happening). How this could happen with the Mosquito and not my other modules? Well, I checked and it appears I had not used those actuators on any of my other modules. Thus the apparent anomaly with the Mossie.
However, I am now flying at 100% efficiency and my thanks to those who offered help and encouragement!
Chris
chris455's post in This is a real enigma. I would really appreciate help from those who are willing................ was marked as the answer