Reposting from the reddit /r/plex questions thread. Didn’t get an answer there so maybe I’ll have better luck on the homefront:
Is there a way to force a series to match against live tvdb or to request that Plex update their cached version? Adding a series (kids show named LoliRock to be specific) doesn’t pull down any covers or artwork but it is pulling down the episode names and other metadata. It was confusing the heck out of me because I could see on live thetvdb.com that there were covers and artwork but I couldn’t get it to populate in Plex. I tried a bunch of fixes I found on the forums and [reddit /r/plex] but none worked. I finally came across the URL for Plex’s tvdb cache and found the show on there and there was no artwork in the cache, so that finally answered that question on why it never pulled anything down. It has been like that for over a month and doesn’t seem to be updating the cache unfortunately for that series. I know I could just download and apply the art myself but would like to get it working automatically as it should.
Live link: http://thetvdb.com/?tab=series&id=289579&lid=7
Plex cache (where I assume it pulls metadata from after matching in plex?): http://thetvdb.plexapp.com/?tab=series&id=289579&lid=7