Server Version#: 1.18.4.2171
Player Version#: 4.20.1
When you’re editing a library on your Plex Server via Plex Web, and go to the Episode sorting dropdown… it shows Library default, but you’re in the library trying to set the default. I’m not sure if it’s been like this forever, but seems a little strange.
It’s the exact same dropdown & description of the setting, as found in a TV Show’s edit screen. Wondering whether the wrong dropdown is being shown in the Library settings?

I would’ve thought it’d be something like this instead:
Library Level:
Oldest First & Newest First . Description: How to sort the episodes for a TV Show, in this library.
TV Show Level:
Library Default , Oldest First & Newest First . Description: How to sort the episodes for this show.
It’s just I can’t see any other dropdowns at Library level with an option for Library default, as that option is usually found either in a TV Show, Movie or other contents’ edit page. 
