title: UIPageViewController transition 'Unbalanced calls to begin/end appearance transitions for '
body: <p>When I navigate through <code>UIPageViewController</code> faster than its transition animation I am getting '<code>Unbalanced calls to begin/end appearance transitions for &lt;MyDataViewController&gt;</code>' and one of the two views in landscape isn't shown until I try to turn the page.</p>
  
  <p>Anybody has an idea to solve this bug?</p>