In 4.1 beta 1, when new record added to the store or updated, values returned by server for fields with persist set to false will be ignored. Based on the comments in source code, it seems like a new direction being taken in 4.1 to prevent "default" values from server to propagate to Model... But I would advocate that this is a bug since it
  • breaks behavior of previous release
  • addresses only one corner case scenario
  • inconsistent - call store.load() and all "default" values will get into non-persistent fields