The old tv show metadata agents will very likely see no further bug fixes. Because there is a new tv show agent being developed right now. [BETA] New Plex TV Series Scanner
If you are using English as your metadata language, you could switch to this agent already. If not, I can’t recommend doing so, yet.
In general, I strongly advise you to place any custom posters as files into the folder structure of your media. Do not use the drag&drop/upload methods to upload posters in the plex web app.
Please see the documenation on where to place the files and how to name them:
