HDR10/Dolby Vision MP4 - Container (mis)identified as MOV?

[forbis]

Can you share your jellyfin and ffmpeg logs via privatebin.net?

And what was the goal of encoding an, I'm assuming, already 4K DV file with Handbrake?

The goal is mostly storage conservation and to reduce the need for on-the-fly transcoding for devices with bandwidth restraints. I also convert to MP4 to prevent remuxing MKVs - I would prefer direct play wherever and whenever possible. I was able to get the 44GB source file down to 6.5GB with very little discernible quality loss.

I started my library using the .m4v extension, and it just sort of stuck - but the files are 100% MP4s and I've even tested this using the .mp4 extension to the same results.

I checked the logs, they don't seem to indicate a reason for the remux (other than unsupported container). I've included the logs from around the time I started a stream nonetheless.
Jellyfin log (from ingestion of new file to start of playback) https://privatebin.net/?db33843c120d1320...MJsuaV5Mk3
ffmpeg remux log https://privatebin.net/?ae174c40f8ed67a3...1oWzu2XCiQ

What's strange to me is that even when not in playback, in the "Media info" section the container is listed as "mov". This would lead me to believe it's being identified as such when Jellyfin first detects the file and scans it for metadata. I've also compared the output of ffprobe on these files and compared it to other m4vs I have encoded and the output is identical down to the "Input #0, mov,mp4,m4a,3gp,3g2,mj2", and "major_brand    : mp42". I have to assume Jellyfin server is overriding the container type at some point along the line specifically due to the Dolby Vision content.