title: Unbalanced calls to begin/end appearance transitions for <UINavigationController: *****>
body: <p>Here is my code:</p>
  
  <pre><code>UINavigationController *navigaitonController = [[UINavigationController alloc] initWithRootViewController:tips];
  navigaitonController.modalPresentationStyle = UIModalPresentationCustom;
  navigaitonController.transitioningDelegate = tips.transiction;
  navigaitonController.modalPresentationCapturesStatusBarAppearance = YES;
  [controller presentViewController:navigaitonController animated:YES completion:nil];
  </code></pre>
  
  <p>when tips controller be presented or dismissed, the console log:</p>
  
  <pre><code>Unbalanced calls to begin/end appearance transitions for &lt;UINavigationController: *****&gt;
  </code></pre>
  
  <p>what's the problem? Please help me.</p>