Passenger wing mirror problem

We have a 2005 Superb Elegance Mk1 where you have the option of the passenger side wing mirror automagically changing position when reverse is engaged - it does this as part of the seat memory function. We typically don't use this feature, however.....

Recently, this mirror has taken to initialising itself to pointing at the floor when the car is first unlocked (ignition off and reverse not engaged). I've also now discovered that I can't get it to consistently readjust when reverse is engaged or disengaged.

Has anyone seen anything similar?