On all of my synced Windows 8 and Windows RT machines, the Games app live tile is no longer updating; i.e., it is not showing my profile picture or Gamerscore, just the plain controller icon.
In addition, when I start the app, my Xbox Live Avatar does not show up even though the app shows me as being logged in and I can view my friends list. Instead, I see a blank avatar placeholder. Also, the normal profile options are missing; instead, I see the same options that are normally displayed for friends: Add Friend, Compare Games, and View Profile. (Naturally, if I click View Profile, the resulting page is blank and the app says it is unable to connect to Xbox Live.)
At first I tried all of the published work-around and troubleshooting suggestions: syncing app licenses, uninstalling and reinstalling the Games app, modifying my Avatar's appearance on Xbox.com, running the Metro app troubleshooter, etc. When none of these worked, I checked and realized that this behavior is universal across all of my machines. I also verified that the Games app is working correctly for my wife on the same machines where it is broken for my account. This suggests that this is not an issue with my local PCs, but is some problem with the app and my account.
For what it's worth, the Games hub on my Lumia 900 running Mango is working, and I can edit my avatar and Xbox Live profile via the phone. There is also no problem when logging in via the Web at xbox.com.
There is a history of similar problems being reported in the various Microsoft Answers forums, so I don't think this issue is isolated to me.
Thanks for listening.