Hi,
Sadly no solution but I noticed a similar problem yesterday with 3.4.8.
I started driving with the screen on, after a while (10-15m ?) the screen went dark.
Since i was driving a motorcycle this was a big problem (cant operate the screen with gloves, and you dont want to do that driving 120km/h anyway).
But then the screen came back on, but it was basically alternating between the lock screen with a text instruction on where to go next, a blank screen and a map screen where the orientation flipped (probably caused by coming from the lock screen ?).
Not sure if this is a bug or a feature, but I really need a way to keep the screen active ( I think this was one of the first times I used the 3.4.8 for navigation as i was using an older version before which did not have this behaviour ).
Is there any setting to control this ? The options under 'Turn Screen On' in navigation settings to only go from never to 60 seconds, there is no always on option (or so it seems)... ?
Bram