[BUG] FFmpeg 'color adjustment' messes up 4:2:2 colors

[OhNoxius]

Enabling FFmpeg 'color adjustment' messes up the colors when encoding 4:2:2 video to x264 with color space 'i442'. To reproduce using 2021.04.12.1 :

• input 4:2:2 video
  
• enable FFmpeg 'color adjustment' (no need to adjust parameters)
  
• x264
  • color space: i422 => wrong colors
    
  • color space: i420 => right colors
    

Interestingly the filter preview works fine and shows the effect of adjusted color parameters. Attached is a frame from the original 4:2:2 video and the corresponding frame in the encoded x264 in i422 (no other filtering is applied, only cropping + letterbox).