title: CollapsingToolbarLayout exitUntilCollapsed causes layout issue with NestedScrollView
body: <p>I have a simple collapsing toolbar inside a fragment, which is inside a viewpager with tablayout:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;android.support.design.widget.CoordinatorLayout
      xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:tools="http://schemas.android.com/tools"
      xmlns:app="http://schemas.android.com/apk/res-auto" android:id="@+id/main_content"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:fitsSystemWindows="false"
      tools:context=".MainActivity"&gt;
  
  
       &lt;android.support.design.widget.AppBarLayout
          android:id="@+id/appbar"
          android:layout_width="match_parent"
          android:layout_height="192dp"
          android:fitsSystemWindows="true"
          android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"&gt;
          &lt;android.support.design.widget.CollapsingToolbarLayout
              android:id="@+id/collapsing_toolbar"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:fitsSystemWindows="true"
              app:expandedTitleMarginBottom="80dp"
              app:expandedTitleMarginEnd="64dp"
              app:expandedTitleMarginStart="48dp"
              app:layout_scrollFlags="scroll|exitUntilCollapsed"
              android:background="@color/red"&gt;
  
              &lt;android.support.v7.widget.Toolbar
                  android:id="@+id/anim_toolbar"
                  android:layout_width="match_parent"
                  android:layout_height="?attr/actionBarSize"
                  app:layout_collapseMode="pin"
                  app:layout_scrollFlags="scroll|enterAlways"
                  app:popupTheme="@style/ThemeOverlay.AppCompat.Light" /&gt;
          &lt;/android.support.design.widget.CollapsingToolbarLayout&gt;
      &lt;/android.support.design.widget.AppBarLayout&gt;
  
  
      &lt;android.support.v4.widget.NestedScrollView
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          app:layout_behavior="@string/appbar_scrolling_view_behavior"&gt;
  
          &lt;LinearLayout
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:orientation="vertical"&gt;
  
  
          &lt;/LinearLayout&gt;
      &lt;/android.support.v4.widget.NestedScrollView&gt;
  
  &lt;/android.support.design.widget.CoordinatorLayout&gt;
  </code></pre>
  
  <p>When my fragment first loads it all works fine but when the fragment is reshown after swapping between tabs, I can no longer scroll to the very bottom of the NestedScrollView. The missing section of my content is the same height as the Toolbar (changing the toolbar height changes the missing section height).</p>
  
  <p>Here's the unscrolled view:</p>
  
  <p><a href="https://i.stack.imgur.com/YnZwm.png" rel="noreferrer"><img src="https://i.stack.imgur.com/YnZwm.png" alt="enter image description here"></a></p>
  
  <p>When scrolled to the bottom there's a section not shown, in this example there's another 'Text 6' TextView that's off screen and can't be accessed.</p>
  
  <p><a href="https://i.stack.imgur.com/x0WBo.png" rel="noreferrer"><img src="https://i.stack.imgur.com/x0WBo.png" alt="enter image description here"></a></p>
  
  <p>On some tabs (I have 6) I can never access the missing section, on others it follows the pattern:</p>
  
  <ol>
  <li>Can scroll to bottom</li>
  <li>Change tab and back again</li>
  <li>Cannot scroll to bottom</li>
  <li>Change multiple tabs so that the fragment is killed</li>
  <li>Fragment is re-inflated when selecting tab again</li>
  <li>Can scroll to bottom</li>
  </ol>
  
  <p>Any help would be appreciated.</p>