Bingo ! I see the same using FSUIPC, ActivePie, GSX and SODESeems like a few have managed to have come across what's causing the issue and I've just been ensuring I can replicate it which I've been able to do constantly in SODE, GSX, Active Sky and Pro ATC.
Issue seems to be that the last number you press is being stored somewhere and is being called upon when you load a SimConnect window, instantly selecting said option in the menu.
So for example if I press "3" and then proceed to load up a SimConnect window it'll instantly select option 3.
Looks like a key repeat/not flushing keyboard buffer issue !
LM .... thoughts ?