Server Version#: 1.18.6.2368
Player Version#: 2.13
I see several locked threads about this from the past, so this problem is not unique to me and has persisted for several years, and unsurprisingly it has not been addressed.
Once I’m on my “On Deck” screen and click either the Play or Shuffle icons in the upper right hand corner, nothing happens.
The behavior in other clients does not matter as I am here specifically asking about the behavior of the Apple TV client.
Making sure this stays active and visible.
Up. Because this is obnoxious.
Still no reply?
Surprise, surprise.
Can you post a photo of the screen you’re on? Because I can’t navigate to an “On Deck” screen – there’s my Home Screen which has an On Deck hub; and my Recommended tab which has an On Deck hub. But I can’t find an On Deck screen (with or without play/shuffle buttons) on the Apple TV… v2.14 of the Plex app.
If you have over 25 items in your On Deck hub, on the home screen, scroll all the way over to the end and you’ll find the “More…” button which, when clicked brings you to the list of everything in your On Deck queue.
If you don’t have that many items in your On Deck hub, you may - in the desktop web app - wish to go to your server settings, scroll down on the left to “Library”, then scroll down on the right until you see the fields “Weeks to consider for On Deck and Continue Watching” and “Maximum number of On Deck items which will appear.” Change those values to a number like 200 or 300.
On your Apple TV - you’ll need to refresh your home screen, which is probably best accomplished by force quitting the app, waiting a moment, and then re-opening the app.
If all goes well and your library is large enough, you should have enough items in your On Deck hub to trigger the “More…” prompt.
Otherwise, I’m unable to recreate the issue that you have, so it must not be an issue at all.
This won’t help, but on my Roku On Deck Shuffle works as expected and browsing On Deck is easily accomplished in, not one, but two ways:
By setting the max number of On Deck items displayed to less than I’ve got in On Deck (Settings/Library) - then go right to the end and ‘More’
or
Hit * while in On Deck and select Browse On Deck from the list of options.
Might be something the Apple Wing wants to explore.
They need only walk down the hall to the Roku Wing, but they’ll probably trip over some of the junk outside the FireTV Wing - they must be remodeling in there - they sure aren’t doing anything important.
When I said that I was unable to recreate the issue that you were having, I meant the inability to find the “On Deck” screen.
The play and shuffle buttons are still just decorative buttons.
You have a strange notion of the physical layout of Plex the company. 
Don’t burst my bubble.
It gets me through the day…lol
I’m dyin’ to know - does shuffle work on your stuff or not?
Need to set up the test case but I don’t doubt the OP. Once I’ve got it set up with steps to reproduce, I’ll follow-up with the devs…
I’m running the latest version via Test Flight (2.15 #14648) and the shuffle button works the first time I use it entering the On Deck screen (from the Home Screen / “More”).
However, if I back out of something playing and then navigate back to the shuffle button and click it again, nothing happens.
If I leave the On Deck screen and return, and then navigate to the shuffle button, it works again, and I get a different episode.
So yes, a bug with kind of a workaround. I’ll send it along to the devs…
Love the tongue and cheek, could not resist that one. Lol 
I will be testing the fix for this issue in updated version as soon as the fix is available via TestFlight. No ETA currently.
In recent tests of the latest version available to me in TestFlight, I have confirmed the shuffle and play buttons work from all the “screens” via “More”(including “On Deck”) from Home Screen hubs EXCEPT for “recently added tv”.
I’ve updated the dev with this information and will test again once I have access to the fix for this one hub/screen.
thanks for your attention to this matter.
One more thing you may want to ask the devs -
If put on shuffle, will the queue continually update or will the contents of On Deck at the moment you hit shuffle be all that winds up in the queue until the next time you hit shuffle?.
Live updating would be ideal, or gasp the option for live updating.
By continually update, do you mean on the Home Screen, the On Deck screen or both? I suspect it should continually update both but I’ll test soon-ish…
I assume both will happen, but I mainly mean the play queue. After I’ve gone through everything that was “On Deck” at the time I hit shuffle, is that the end, or will the play queue continue to update and add the new On Deck items (after I finish S1E4, S1E5 will be added to the queue)
Ah excellent question, I’ll see what I can find out.
