Transcoding not working on docker with QSV

[pxr5]

I can't help with this I'm afraid as I have exactly the same problem with an Intel Braswell CPU in a Synology NAS. It works fine with VAAPI, but any configuration with QSV will cause a fatal playback error with the same log info as in the OP's post. I've tried pretty much every configuration of the transcoding settings in Jellyfin. This is my compose file - I've tried it as root too with no joy. I've tried this as well ("Prefer OS native DXVA or VA-API hardware decoders") and paired back everything to h.264, low power settings on/off etc.

services:
jellyfin:
image: jellyfin/jellyfin:latest
container_name: Jellyfin
environment:
- PUID=1027
- PGID=65536
- TZ=Europe/London
group_add:
- "937" \ # Change this to match your "render/video/input" host group id and remove this comment
volumes:
- /volume1/docker/jellyfin/cachecache:rw
- /volume1/docker/jellyfin/configconfig:rw
- /volume1/video3/TVTV:ro
- /volume1/video3/MovieMovie:ro
devices:
- /dev/dri/renderD128dev/dri/renderD128
- /dev/dri/card0dev/dri/card0
ports:
- 8096:8096/tcp
network_mode: host
restart: unless-stopped