The issue revolved around installing backwards compatible games from disc, with players being told that there was a "problem getting this content". However, Xbox confirmed this had been "fixed" in an Insider update last week:
"Fixed an issue where Xbox 360 and Original Xbox backward compatible discs would display "There's a problem getting this content" on Home if the Play disc automatically setting was disabled."
Despite the apparent fix, players are still reporting the same issue, so we're assuming it hasn't been rolled out to absolutely everyone yet. Here's an example from the Xbox Support subreddit earlier today:
Fortunately, there's a temporary solution - you need to turn on "Autoplay" in the settings.
This was explained by Xbox developer OscarK on ResetEra earlier in the month:
"Update: we have identified the issue - it is a UX regression in the August update that causes discs with minimal metadata (such as X360 discs) to accidentally throw an exception and be treated as unsupported discs. The underlying installation, activation and licensing systems are unaffected, so there are a couple of workarounds:"
"- Enabling Autoplay (Settings > Devices & Connections > Disc > Play disc automatically) will cause the game to be installed on disc insertion. This setting is enabled by default.
- Push install of the game from the Xbox mobile app."
We're working on a fix internally and assessing impact and next steps, as well as re-examining test passes to ensure this does not happen again in the future. Apologies for the issue but as always thanks for the reports!"
With any luck, this should all be done and dusted in the very near future, but it's worth keeping this workaround in mind if you end up needing it anytime soon. You can always count on Team Xbox to fix things like this pretty quickly!