RC3 3D/2D issue on FireTV2

[I think I had that kind of issue some time before, but can’t recall what solved it – the search function requires at least 4 letters, which is a bit too much for “3D” ]

Though (default) video display mode is set to “2D” for “3D” movies they get displayed in stereoscopic mode on my FTV2. I think it was still working as expected with RC2.
However the same “3D” movies are porperly shown in “2D” with the same settings on my other platforms, be it either RC3 on Windows (10) or Android Galaxy Tab 2 (cyanogenmod) or even on my TV sticks …