Yes. That was me...
Sufficed to say, when using 'direct source', any video that's been encoded with 576 vertical pixels, should be output with 576 vertical pixels. Even if the horizontal resolution is greater than 720. It makes no sense to up-scale a 1024x576 pixel image to 1280x720 pixels. Indeed, is there anything in the EDID specification where it says this should be done?!
And sadly... 720x576 (4:3 and 16:9 DAR) 'pure interlaced' (50 field) sources are now being output as progressive, even though they are listed in the EDID specification. It was working before
No question that there is something wrong with the MKV player since the last official firmware release.