title: Why is change detection called twice?
body: <p>I have a simple test-component with no logic.
  I render this component.
  Why is the DoCheck hook called twice?</p>
  
  <p>So far I understand, DoCheck is called for every change detection.
  But there is no change.
  I just render the component and DoCheck is already called two times.
  Also ngAfterContentChecked and ngAfterViewChecked.</p>
  
  <p><a href="https://i.stack.imgur.com/WCtX3.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/WCtX3.jpg" alt="enter image description here"></a></p>