curious… do you have more than one TV library?
On Deck in manual mode seems to only show items from one library. Don’t know how the app/server chooses the library. I would imagine if there were no On Deck items in the library Plex chooses, there would be no On Deck.
In automatic mode, it shows items from both libraries. Any customization of the home page (removing an unwanted hub, for example) puts the device in manual mode, and On Deck shows just one library again.
Or, it could be the return of the bug that was here, that I found a work-around that gave back my “On Deck”