This is Plex Android.If you play the audiobook a bit and stop it then leave the player view (back to the book page) and scroll down passed the star ratings you'll see the tracks listing. If the app has saved the playback position you'll see the orange bar marking the latest point on the track ... tap the track and it should offer to play from the saved position.
This wasn't obvious and I think hitting the big play button will reset the saved point. Not very slick. And so far not sync'ed between devices.
You did this?"Resume from ..." and "Play from beginning" options are dispayed -> check
"Resume from ..." actualy resumes -> nope, still starts from the beginning.
Seems either the TV mode or the ATV implementation has a bug.
In my evaluations, I always use downloaded books for Audible, Booksonic and Plex. Both Booksonic and Plex have lost my listening position.Do you have the same issue with Plex client with a downloaded book?
Downloaded it, just for you!