Hi,
I am living in Germany, bought the Forma in the Netherlands because you can not buy it in Germany.
If you look closely at the pictures the Forma has 4 gray bars forming a border (pushed up the contrast to enhance visibility). The interesting thing is, that this border is equal to the dark border shown in the settings dialogue. Maybe it's some kind of burn in effect from the factory tests?
That could be a reason why sometimes a factory reset solves the problem and sometimes not.