The Mk4 will only turn off as follows:

ignition off, key out
all doors and bonnet closed (boot can stay open)
to be extra sure, close all windows and sunroof as well
then after 60 seconds (sometimes a bit longer) the Mk4 will switch off

The Mk4 nav monitors ibus activity and switches off only after 60s of no ibus data traffic happening

If something in the car is still talking, the Mk4 will stay awake a bit longer