Wouldn't we like to know?
I was watching a video about the 722.6 tranny yesterday and it pointed out that the MB tranny was different from about every other electronic trans in that the shift solenoids only activate during the shift. They do not stay applied. This allows the car to fail safe in a high gear (and hopefully get you home). Once restarted if in failsafe it will start in second gear.
I mention this to point out that the problem is possibly not electrical. My guess is a valve stuck briefly in the
VB.