I’ve recently switched to the new Plex agent for TV series, which seems to be working great apart from Mad Men (2007). The series is matching fine (it pulls the show description and posters etc.), but is not pulling season or episode data (i.e. everything is just Episode 1/2 etc., and no images). Using the old TVDB agent works fine, so it’s not how the files are named, as far as I can see.
I would try a Plex Dance. I have Mad Men on my server and everything pulled fine. All the episodes have names and descriptions. Also how do you have your files named?
Try changing the agent to the new one, and the episode ordering to TheTVDB, that is how I have mine set up for a multitude of reason and have no issue.
Super strange, I tried again last night and it worked. I hadn’t changed anything, but now it’s pulled the metadata. Don’t understand why but I’m glad it’s fixed now