title: iOS App shuts down when notification center and recently used app list are opened
body: <p>My iOS app simply shuts down when I open notification center while the app is visible and in focus. Same thing happens if I double click the home button to show the recently used apps list.</p>
  
  <p>This would seem to be an application lifecycle issue, but no errors are reported in Xcode. </p>
  
  <p>How should I go about debugging this problem?</p>