Server: 1.21.1.3766 on DS918+
Client: 8.11.0.22186-beta on Shield 2015 Pro
Partially fixed in 8.11.0 (non beta).and 8.11.0.22093-beta.
When on the TV show pre-play screen, the “Mark as Played” button now works, and the results are reflected immediately on-screen for all seasons (or episodes if only one season).
Results are not immediately reflected on the TV Show Library main page (which displays all shows). If, from a TV show pre-play screen, I mark a show as played, then back up one screen, the show cover art still displays the number of previously unplayed episodes (as if I had not marked anything as played). If I change to another library then return to the TV show library, the show cover correctly displays played/unplayed status.