I've also experienced what you describe. It's not "fatal", just annoying. As you stated, everything came back normally after a restart. I had similar problems with my 2014 Accord Hybrid. Eventually the dealer changed something and the problem was resolved.
I have noticed that sometimes when I start the car the display mode doesn't return to the mode which was selected when I last drove the car, i.e. instead of returning to Audio mode the display shows Map mode. Pushing the Audio button fixes the issue. However, it seems as though the display mode would return to its previous state. Again, annoying, not "fatal".