Can't read achievements for certain users

I'm experiencing some inconsistent behaviour when trying to read achievements from my app. I have 3 tests accounts, 2 of which I can read achievements. However the 3rd account always returns an empty array. All 3 accounts have the publish_action permission and I've tried using both the user and app access_token. Here's the query:

https://graph.facebook.com/{uid}/achievements?access_token={ap开发者_StackOverflow中文版p_access_token}

or

https://graph.facebook.com/{uid}/achievements?access_token={user_access_token}

Now I know the 3rd account has achievements as I get an error when I try to give it an achievement it already has and the game ticker correctly shows the achievements it has earned.

Make sure the third user has granted "user_activities" extended permissions so that the activities can be read, not just published. You can verify this by calling /me/permissions.

Have you checked the facebook layout regarding achievements in your app? since in my FB account I can roll over my own achievements and I get a full list of the achievements configured with each game and in other acocunt that info is not available. The other distinctive feature is I see my thumbnail picture over the main facebook bar (the blue one next to log in)