(In reply to Christian König from comment #36)
> Ah! Ok that's something different. As long as the system was completely off
> (defined by no power to the GPU) there shouldn't be any influence from the
> previously booted os.

Well, I would say the GPU didn't have power. I mean some parts of the
motherboard stay powered for e.g. wake on LAN, but otherwise? I can try whether
disconnecting the power makes a difference, if you feel, that would be helpful
in tracking this down.