I've seen this off and on too, but any time I've tried to investigate it more it seems to stop happening. Do you have specific steps that cause this to always happen? I reset to default prefs then started a C172 G1000 flight at KSEA and PMDY and only saw the brighter version of the right side display, for example. I also tried changing to a couple different aircraft and back and still couldn't see the dim one.