I just discovered a bug with the sleep timer feature.
The option “End of album” is only visible on the last track on the album and none of the other tracks and it’s kind of useless on the last track. It should probably switch and be visible on any other track than the last, and I assume that is the intent.
Have you considered that your screen might just not be tall enough? i.e. have you tried to swipe the menu upwards?
Are you calling up this menu from the ellipsis at the end of each track line? If you do, it relates to the track. And if the track is not the last in the album, the “album” menu item won’t appear.
Try instead the ellipsis at the bottom of the player.
Do you have an album coming up in the play queue for sure?
Yes. You can see the next album in the images.
Playing around some, and I just discovered that the “End of album option” shows up when I start a new play queue with the same album. Weird. 
However, when I start playback from the “recently added” playlist it doesn’t show up, but only for that specific album in the queue, which is kind of odd.
E: No, it does happen on a few other albums when started from “Recently added”, but they all work fine when played alone. I think the bug is triggered by playlists somehow. The albums are listed in correct track order in “Recently added”.
More playing around: I think “end of album” actually only show up on the last album in any playlist.
IIRC playlists don’t have the “album” context in them. They are just a bunch of single tracks.
You will have to start playback as “album”.
Well, it does work on the last album though. Seems like a weird behavior if Plexamp is able to detect that it’s playing an album, but only when it the last one in a playlist.
E: And isn’t the entire point of having a “sleep on album end” pointless if you only play a single album that has no more tracks after it.
