You downloaded someone else’s compressed re-encodes, then, not the actual official Team Negative1 releases.
Official releases of 4K77 and 4K83 are MKV files with multiple DTS-HD MA and Dolby Digital audio tracks, or Blu-Ray ISO files that also have DTS-HD MA and Dolby tracks. None of them are MP4/M4V and none of them have AAC audio.
Gotcha. I may have been getting MKV / M4V confused as I was converting the UHD download to 1080p to author a Blu-ray. I did have the original TN1 MKV with the 5.1 audio, so I’m all good now!