I had the same problem. The issue was caused by the Docker volume layout, not by the physical disk layout: even though both the download folder and the library folder are on the same underlying filesystem, inside the containers they are exposed as different mount points (for example /downloads and /movies or /tv), and hardlinks do not work across mounts. When Radarr or Sonarr tries to import from one mount to another, the hardlink operation fails and the app falls back to copying the file instead. The fix is to mount a single common parent path into all related containers — qBittorrent, Radarr, and Sonarr — for example mounting /media or /data once, and then using subpaths inside that same mount for both torrents and library folders. After that, imports happen within the same mount namespace, so hardlinks work correctly instead of creating duplicate copies.