Can't control existing cast
I used to be able to go to the web app and click Cast and if something was already playing on my Chromecast, I could control it through the Plex web app. Now I can't, when I click the cast button the Plex interface isn't refreshed with the currently playing media.
The only way to control the media is to start the cast from the web player and leave it open. You can't close it and open it again and resume control, like you used to be able to.