I exported a video to YUV lossless. Upon importing that video into REAPER, red and blue channels are swapped. VLC won't play the file, but Windows Media Player does and plays it correctly, so it seems that REAPER's decode is at fault.
(Or rename it to "Alternate reality filter"
)
(BTW, since it's 2019, would you consider relaxing the 800x600, <64kb attachment restriction? ;P )