Strangely enough, my GoFlight pro did exeactly as described (darn near crashed my PC-12 on landing at W16)
I have no idea what caused this, and it began suddenly. However I was using P3D V3 at the time (I have V4 installed)
av8r13, have you made any progress? Please let me know if there is anything I can help with. I am currently at a loss...