I have 2 instances of PMS running, one on my home Mac Mini, one on a remote seedbox.
Both versions are the same, and all settings are identical between the two.
However my Movies library on the remote one does not download metadata/artwork as it should - I get a generic thumbnail and no real metadata.
On the Mac Mini at home, all metadata is downloaded ok, with correct artwork.
On the remote server, if I manually search for the info, it comes up fine