title: Block inside block = EXC_BAD_ACCESS
body: <p>I have a singleton class the handle all the Game Center logic: </p>
  
  <pre><code>typedef void (^GameCenterCallbackFinishUpdating)();
  
  - (void)getAllMatches:(GameCenterCallbackFinishUpdating)onComplete
  {
      [GKTurnBasedMatch loadMatchesWithCompletionHandler:^(NSArray *matches, NSError *error)
      {      
          //Do stuff here... 
          onComplete();
      }];
  }
  </code></pre>
  
  <p>From another viewController I use: </p>
  
  <pre><code>[[GameCenterHelper sharedHelper] getAllMatches:^{
  
      [self.myTableView reloadData]; 
  
  }];
  </code></pre>
  
  <p>It works great when I'm in the app, but once I close the app (background) and then start it up again, I get: </p>
  
  <pre><code>    onComplete();     ---- Thread 1: EXC_BAD_ACCESS (code=2, address=0xc)
  </code></pre>
  
  <p>What am I doing wrong here? </p>