I havent seent that before, its very strange. Perhaps it is the Ground on the car.
maybe a loose ground could cause weird electrical problems like that.
I'm sure someone will have the right answer.
'92 300CE - Sold
2004 C240 - C7 Wheels
2015 ML350 - P1, Pano, Ash poplar wood, Sport Dinamica interior, Running Boards Keyless go.