I'm seeing a surround sound issue on my Nvidia Shield. Noticed that my Shark Tank recording which lists as DD5.1 was playing as stereo on my receiver even though I have surround set to on in the Channels app.
In the Shield settings you can force to Dolby Digital so I tried that. It now shows Dolby Digital + on my receiver but there's still nothing coming out of the left/right rear channels.
Saw a similar issue in the Apple TV forum when I searched but posting in the proper forum.