Hi,
as far as i understood, its an automatic gearbox. As you said, it will only happen in the morning, when the car is cold.
So i first of all, drive to a VW dealer and ask him to hook up the black box to the diagnostics. I would guess, that the gear box has an extra temperature sensor and somethings wrong there, or its a humidity problem, because there is condensed water on a contact or in a black box.