My dash did a similar thing once. One time when I was driving I accidentally hit the battery tie switch (emergency start, in case of dead engine battery.) Everything did just as you described and then went back to normal, and has never happened again. I am more careful when reaching for switches now.
The only reason I bring this up is I was thinking that after reading your issue, if you have a loose connection in that switch or wiring while going down the road and hit a bump could this cause your issue? or the solenoid it operates is going bad? The switch momentarily connects the house 12v battery to the engine 12v battery. Going down the road my RV engine charges both batteries via two different paths, obviously momentarily connecting these two charging paths from the same source is bad for the your alternator. This thinking just made me think maybe your alternator is having intermittent failure, precursor of possible future failure. That is easy enough to check just take it to one the the car parts stores and have them test the engine battery and charging system. Since the problem is intermittent it may not present itself while they are testing and be inconclusive.
A long shot and ball parking here and most likely not your issue, as Gary and the others have said.
