Storage and/or binding issue with docker-compose on macOS

I recently used docker compose to create a container with numerous services, one of which was Radarr:

    container_name: radarr
      - PUID=${PUID}
      - PGID=${PGID}
      - ${MEDIA_DIRECTORY}/movies:/movies
      - ${MEDIA_DIRECTORY}/downloads:/downloads
      - ${INSTALL_DIRECTORY}/config/radarr:/config
      - 7878:7878
    restart: unless-stopped

In the .env file accessed by that docker-compose, I had these variables for the media and install directories: MEDIA_DIRECTORY=/Volumes/media_raid1/srv/media INSTALL_DIRECTORY=/opt/mediaserver

Of note, /Volumes/media_raid1/ is a 14tb external drive plugged into my Mac.

The docker-compose process went fine, but here’s my issue: the /Volumes/media_raid1 drive has ~14tb of free space. However, when I’m adding a movie in Radarr, I see this, basically saying I have ~193gb free: Imgur: The magic of the Internet

Radarr says it’s mapped to the movies folder: Imgur: The magic of the Internet
and according to the docker-compose file, plus the MEDIA_DIRECTORY value, its mountpoint should look like this: /Volumes/media_raid1/srv/media/movies:/movies

And when I look at /Volumes/media_raid1/srv/media/movies, every file handled by Radarr is there, with ~14tb to spare…

So where is that ~193gb number coming from? Is there some kind of issue between macOS with an external drive and docker?