Save in Mongoose has unexpected behavior

gistfile1.txt

var saveEvent = function(eventObject, userId, ref, callback){
    
    var theEvent = new CalendarEvent();
    
    theEvent.title = eventObject.title;
    theEvent.allDay = eventObject.allDay;
    theEvent.start = eventObject.start;
    theEvent.end = eventObject.end;
    theEvent.url = "empty";
    theEvent.color = eventObject.color;
    theEvent.ref = ref;
    
    var eventDate = new Date(eventObject.start);
    arrayLocation = 1 + (((parseInt(eventDate.getFullYear())) - 2011)*12) + parseInt(eventDate.getMonth());

    console.log('Searching for userId in event ref collection: ' + userId);
    CalendarEventReference.findOne({ id: userId }, function(err, resultReference){
   
        if(err){
            console.log('Error in finding calendar reference collection: ' + err); 
            callback("Cant find CalendarEventReference for user");
        }
        else{
      
            resultReference.ref[arrayLocation].allEvents.push(theEvent);

            resultReference.save(function(err){
     
                if(err){
                    console.log('Error in finding calendar reference: ' + err);
                    callback("Cant save allEvents in CalendarEventReference");
                }
                else{
                    console.log('Succesfully saved Event'); 
                    callback("Successfully saved Reference");
                }      
            });
        }

    });

}


---------------------------- Mongoose Schema ----------------------------------------


var CalendarEventReference = new Schema({
    
   id   : Number,  //Users id 
   ref  : [CalendarMonth]  
    
    
});

var CalendarMonth = new Schema({
 
 id          : Number,
 allEvents   : [CalendarEvent]
   
});


var CalendarEvent = new Schema({

   title      : String,
   allDay     : Boolean,
   start      : Date,
   end        : Date,
   url        : String,
   color      : String,
   ref : String
    
});