I feed all my devices into my PI from a Marantz AVR and each one has issues with Black Border detection. The annoying thing about it is that the software seems to be able to detect the black borders but then a scene change will confuse it and the top lights will remain off for the next few minutes.
Anyway, to get it working at all the threshold setting needs to be way up to like 70.
With everything that the software does it would seem trivial to correctly detect black borders, I am unsure as to why the software struggles so much with it.