I can’t seem to join AVSForum to respond.
It looks like it uses a forced deinterlace for progressive VC-1 playback in the same way as for interlaced material. This is a bug in the Amlogic hardware decoder under kernel 4.9. So the vertical resolution is halved here as well, just like in CoreELEC…
Looks like? Based on what? Progressive VC-1 is played as progressive on Vero. What makes him think vertical resolution is halved?