The tints appear to be different when the same image with different resolutions is played with ffplay.

[SYamaguchi]

Summary of the bug:
I encoded some video with different resolutions and played with ffplay and found that the color is slightly different. (See attached images.)
On other players (such as VLC), it is fine.
I tested on Windows 11 and MacBook Pro (2019/Sequoia 15.4.1) and it occurred on Windows only.

How to reproduce:

ffmpeg -hide_banner -i <input.mp4> -c:v h264 -b:v 6M -maxrate:v 6M -g 90 -s 1920x1080 test_FHD.mp4
ffmpeg -hide_banner -i <input.mp4> -c:v h264 -b:v 0.3M -maxrate:v 0.3M -g 90 -s 640x360 test_360p.mp4
ffplay test_FHD.mp4 -x 1280  # -x does not affect this bug.
ffplay test_360p.mp4 -x 1280

[SYamaguchi]

FHD image

[SYamaguchi]

360p image

[MasterQuestionable]

͏    Seems like the color primaries havoc.
͏    Probably FFplay made different assumption based on the resolution.
͏    (however which cannot be considered seriously wrong;
͏    for the de facto situation of the havoc)