Check and see if Dolby Atmos is on the second audio option?
For some reason I had the same issue with my 4K discs and my receiver playing DTS X as the default with the Dolby Atmos option as the alternative in the audio options.
Saw someone on Reddit post this, couldn't believe it's finally on sale.
Condemned for $5
http://marketplace.xbox.com/en-US/Product/Condemned/66acd000-77fe-1000-9115-d802534507d2?nosplash=1
Worth a shot, any new Xbox One Destiny players looking to do this feel free to add me. :)
Xbox One Gamertag: Lost Toasty
Here's my referal link: https://www.bungie.net/en/ReferAFriend?code=RAF-NR4-CDG-Y6V
Backup links (just in case) ...