title: NSNotificationCenter defaultCenter iOS 8. Notification is not being delivered to one of observers
body: <p>Prior iOS 8 all works fine. The problem is:
  I have two observers in different classes:</p>
  
  <p>class1:</p>
  
  <pre><code>[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(didFinishParseUser:)
                                               name:USERS_LOADED_NOTIFICATION_ID object:nil];
  </code></pre>
  
  <p>class2:</p>
  
  <pre><code>[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(didFinishParseUser:)
                                                   name:USERS_LOADED_NOTIFICATION_ID object:nil];
  </code></pre>
  
  <p>and notification is posted in some other place:</p>
  
  <pre><code>[FBRequestConnection startWithGraphPath:@"me/friends?fields=id,first_name,last_name,picture.type(small)" completionHandler:^(FBRequestConnection *connection, id result, NSError *error) {
      if (!error) {
          [[NSNotificationCenter defaultCenter] postNotificationName:USERS_LOADED_NOTIFICATION_ID object:nil userInfo:[NSDictionary dictionaryWithObjectsAndKeys: currentUser, @"user", friends, @"friends", nil]];
      } else {
          // An error occurred, we need to handle the error
          // See: https://developers.facebook.com/docs/ios/errors
      }
  }];
  </code></pre>
  
  <p>addObserver method is called for both of mentioned classes, however notification is being delivered just to one observer. If I delete this observer(which receives the notification), then another one receives the notification.
  Prior to iOS 8 both observers receive the notification.</p>
  
  <p>Can you, please, help me with this issue?</p>