So you mean the aircraft that have Garmin glass panels in them have the panels go dark after flying for some amount of time? The dial type gauges are also known as instruments so just clarifying. I’m guessing all the dial type instruments are fine and it’s just your screens going dark?
If so, are you turning on your generator(s)? Batteries running down is simulated and if your generator(s) aren’t charging the battery, panels will go dark. The dial gauges will mostly all work since few need electrical power to operate.
Might be some bug, too. Just spotted this: Cirrus SR22 MFD Blank Screen