title: java.util.ConcurrentModificationException in AppCompatActivity onCreate
body: <p>I am seeing a bunch of ConcurrentModificationException in crash logs. Does anyone run into this before?</p>
  <pre><code>Caused by java.util.ConcurrentModificationException
         at java.util.HashMap$HashIterator.nextEntry(HashMap.java:787)
         at java.util.HashMap$ValueIterator.next(HashMap.java:819)
         at androidx.fragment.app.FragmentManager.restoreSaveState(FragmentManager.java:2472)
         at androidx.fragment.app.FragmentController.restoreSaveState(FragmentController.java:196)
         at androidx.fragment.app.FragmentActivity.onCreate(FragmentActivity.java:287)
         at androidx.appcompat.app.AppCompatActivity.onCreate(AppCompatActivity.java:106)
  </code></pre>