vaapih264dec produces green artifacts on Kaby Lake GPU with some input files

Hi!

I'm running the following pipeline on this input file (426KB, 50 frames):

gst-launch-1.0 filesrc location=input.mp4 ! qtdemux ! vaapih264dec ! videoconvert ! jpegenc ! multifilesink location="frame%02d.jpeg"

and it generates green artifacts (starting on frame01.jpeg, mostly visible on frame37.jpeg).

• It happens with both vaapih264dec and vah264dec elements (gstreamer1-1.20.3-1.1.fc36.x86_64)
• It happens with both iHD (Intel iHD driver for Intel(R) Gen Graphics - 22.3.1 ()) and i965 (Intel i965 driver for Intel(R) Kaby Lake - 2.4.1) va drivers
• It works on another computer with a radeonsi va driver (Mesa Gallium driver 22.1.7 for AMD PITCAIRN (LLVM 14.0.0, DRM 2.50, 6.0.9-200.fc36.x86_64))
• It works with ffmpeg + vaapi + iHD driver with the following command (although it appears that output files have differences in colorimetry and smoothing, for example in frame38.jpg, frames numbering starts at 1 in ffmpeg) : ffmpeg -hwaccel vaapi -hwaccel_device /dev/dri/renderD128 -i input.mp4 -frames:v 50 frame%02d.jpg