No problem in pinging me. As its just a handful of movies I’ll assume your settings are correct. The posters themselves could be locked. Have you checked if you edit one of the movies if the poster you expect to be there is there ? If so my guess is that its locked and you can try this procedure to unlock them Reset all manual poster selections in a library at once or unlock other metadata fields.
If they are missing and they have been added to tmdb a while ago (meaning the plex back-end cache is updated) then my guess is that as plex has been subject to take down requests for the artwork, like Once Upon a Time in the West metadata - #4 by dane22 and it could be effecting these movies and your region.
These take downs may or may not be related to Plex Sued for Copyright Infringement by Press Agency * TorrentFreak but we can be sure plex is certainly having legal issues with public posted artwork, be it posters, fanart or cast profiles.
My recommendation is to always use local assets https://support.plex.tv/articles/200220677-local-media-assets-movies which is not to be confused with local metadata. I know its a bit of up front work but you’ll never have artwork problems once its setup.
