Playlist posters don't get to clients

A little more info. On my Android TV client (nVidia Shield, build 8.21.0.26974), when I open a playlist, the detail page briefly displays the custom playlist poster, then changes to the poster associated with the first track in the playlist.

Going back out to the top Playlist page, some Playlist posters have changed to a random single poster from one album (not the custom poster), rather than the 4-poster montage. Those playlists were created using TeknoJunky’s random playlist tip.