Ensure that the json written to localstorage is in the format expected by ember-data.

Entities with a hasMany relationship should contain an array of IDs, not an array of embedded objects.

Without this fix, embedded objects get written to localstorage which will cannot be restored upon page refresh.

I couldn't figure out why the member "this._data" contains embedded objects. Perhaps it's supposed to as a performance enhancement and the real bug is simply that you shouldn't use JSON.stringify. Perhaps you should be using some other serializer (I had a brief search but couldn't find out how).

I struggled to get any help on this but if someone with more ember experience than me (aka some) can chip in and explain what was going on I'd love to hear it.