title: Mongoose save returns correct saved object, but it isn't save to DB
body: <p>I am doing a findOne, followed by a save. This is to overwrite a previously save object.</p>
  
  <p>The issue is that after saving the res.json() in my callback returns the correctly updated data (aka the myObject modified via my for loop). But the "save" seems to not actually happen as the DB still shows myObject in its old state.     </p>
  
  <pre><code>var pathList = [{id:'x',url:'#'}];
  
  MyObjects.findOne({'_id': _id}, function(err, myObject) {
    //
    for ( var i in myObject.body.module ) {
      for (var j = 0; j &lt; pathList.length;  j++ ) {
        var id = pathList[j].id;
        myObject.body.module[i].channel[id].buffer = {
          url:pathList[j].url
        };
      }
    }
    //
    myObject.save(function(err, data) {
      if (err){
        res.json({'response':'Error in saving track: '+err});
        throw err;  
      }
      res.json({ 
        'response': 'done',
        'data': data
      });
    });
  });
  </code></pre>
  
  <p>This method of findOne > save has worked for me before. So my wouldn't the above code work? Concurrency? Object size?</p>
  
  <p>Any help would be great. Thanks</p>