I also have not had this problem I fly IFR on every flight except for when I am checking out a new plane. I have AI set to 100% and have three major airline traffic from project ai. and Have never experienced this. I have logged in excess of 2,500 hours of IFR flight.
I know of no reason as to why you are havig this problem unless you are running off the battery which will die after awhile and cause your radio to go out.
But you would also lose instruments as well I would think you would notice that.
I know of several aircraft that even if you use Ctrl + E to start engines with it will not always turn the generators on thus you run on the battery and it will die after a while.
I have assigned shift + B to turn on/off the battery
and shift + G to turn on/off the generators with.
