I have Minix Neo U9-H and the latest CoreELEC.
I have noticed that it does not scale mod 4 videos perfectly.
For example if your video is 1920 x 804, you get an artifact on the last bottom line. If you crop the same source mod 8, for example 1920 x 808, it shows it properly.
Any idea if CoreELEC has problems showing mod 4 videos?