Bug is not present when using store.loadRecords instead of Fixtures

gistfile1.js

// ==========================================================================
// Project:   RecordBug
// Copyright: @2011 My Company, Inc.
// ==========================================================================
/*globals RecordBug */

RecordBug = SC.Application.create({
  store: SC.Store.create().from(SC.Record.fixtures)
});


RecordBug.Person = SC.Record.extend({
  name: SC.Record.attr(String)
});

RecordBug.Friend = RecordBug.Person.extend({
  nickname: SC.Record.attr(String)
});

RecordBug.Client = RecordBug.Person.extend({
  company: SC.Record.attr(String)
});


SC.ready(function() {
  RecordBug.mainPane = SC.TemplatePane.append({
    layerId: 'record_bug',
    templateName: 'record_bug'
  });

  var friends = [
    { guid: 1,
      name: "Lorem",
      nickname: "this"
    },
    { guid: 2,
      name: "Ipsum",
      nickname: "is"
    },
    { guid: 3,
      name: "Dolor",
      nickname: "an example"
    }
  ];

  var clients = [
    { guid: 1,
      name: "Lorem",
      company: "this"
    },
    { guid: 2,
      name: "Ipsum",
      company: "is"
    },
    { guid: 3,
      name: "Dolor",
      company: "an example"
    }
  ];

  RecordBug.store.loadRecords(RecordBug.Friend, friends);
  RecordBug.store.loadRecords(RecordBug.Client, clients);

  var before = RecordBug.store.find(RecordBug.Person);
  SC.Logger.log('before: '+ before.length());  //  Should be 6, prints 6
  
  var longQ = RecordBug.store.find([RecordBug.Friend, RecordBug.Client]);
  SC.Logger.log('longQ: '+ longQ.length()); // Should be 6, prints 6
  
  var after = RecordBug.store.find(RecordBug.Person);
  SC.Logger.log('after: '+ after.length());  // Should be 6, prints 6
});