How to chain retrieving model records

I am retrieving a model record, and need to retrieve another one based on a property from the first one. I have the following code:

Code:

MyModel.load(recordId, {
            scope: this,
            callback: function(record, operation, success) {
                console.log('first one: ' + success);


                MyModel.load(record.get('clonedFrom').id, {
                    scope: this,
                    callback: function(record, operation, success) {
                        console.log('second one: ' + success);
                    }
                });
            }
        });

In the first callback, 'success' is true. In the second callback, success is false, even though the response is fine from the server. In fact, operation.success in the second callback is true. It just does not inflate the record. Why?