Why does DLC not download with backwards compatible xbox games?
Solution 1:
Similar to the My Games & Apps menu that shows you all content installed on your XB1, you can see what content you have installed (and ready to install) on a per-game basis.
To do this, press Start on your backwards-compatible game's tile (on the Home screen or in your game library), and click Manage.
This should show a screen similar to your games library, but the "Installed" and "Ready to Install" should just be for your game. Any DLC you own should be in the Ready To Install category, as in the screenshot below.
