title: CoreData: error: NULL _cd_rawData but the object is not being turned into a fault
body: <p>I occasionally get this error when saving to core data. I cannot manage to recreate it.</p>
  
  <p>Does anyone have any experience with this error;</p>
  
  <pre><code>CoreData: error: NULL _cd_rawData but the object is not being turned into a fault
  </code></pre>
  
  <p>?</p>