Are specials requestable in jellyseerr? They aren't in overseerr, so they have to be manually requested in sonarr. Also, sonarr uses tvdb and as I understand it, it's unlikely to ever support tmdb, so if jellyseerr uses tmdb like overseerr does, then that could be another source of confusion if there are differences.
For now if you use sonarr you just have to accept tvdb and set other things to use tvdb where possible (Plex and jellyfin), and accept mismatches where it can't be changed (like overseerr / possibly jellyseerr too since it's a fork)
Maybe they downloaded the zip and then immediately tried to open it in a specific program through the open dialog giving them an error. I see similar mistakes with my parents - they have no concept of where files are, it's just "on the computer" because they rely so heavily on "smart" file picker dialogs that show you everything recent or by a file type no matter where it's actually located.