Option Playlist “UP NEXT - WATCHING” not appear when connect Plex Server

Is it possible that the series that have “On Deck” on Plex appear as “Up Next”? I ask this, because when you add a file to disk (for example) I can click with the right button and add it to an already available list called “Up next - Watching” and then the image appears on Apple TV on Top Shelf. But with Plex files I can’t, why?