-The poster.jpg USED to be immediately and automatically applied
-The theme.mp3 USED to play upon opening the series page
-The background.jpg image USED to be immediately and automatically applied
-This all USED to work while the series was located under the TV Shows library as they used local assets
Fun fact, once you’ve manually linked/changed something, it won’t go back to being automatically selected unless you do the Plex Dance or run some scripts. Never manually select things if you want it to use local assets.
Maybe try changing the seasons folders to say “Season 2015” instead of just “2015”. And play around with it to try and get it to work with the naming. Otherwise, Other Videos is what you need now with the new scanner. You can always select the older scanners.