title: Order of core data objects altered, different between contexts after core data merge
body: <p>I'm seeing a strange issue with the data in my app before and after a merge. I have an app that lets the user refresh so I have a separate context for that thread and any changes are then merged (as i believe I'm supposed to). I noticed that after the refresh, the data updates are correct (items added, removed, etc.) BUT my items are reordered. I can trace this to the different contexts, but have no idea why this would occur. Scenario is:</p>
  
  <p>refresh and use deleteObject on background context
  save
  this triggers merge with notification
  querying the db on the background context shows the correct order
  querying the db on the main context (which should have changes merged to it) shows different order</p>
  
  <p>if I've got things setup with the separate contexts and the merge, why would the data in the main context be different than the one in the background context post merge? i know this is weird, so any help is appreciated!</p>