alloyui diagram loaded from json object but shoing errors on editing

[ravi...@gmail.com]

Diagram saved using below code using .toJSON() :

var jsonData = diagramBuilder.toJSON();

Existing Diagram removed using below code:

diagramBuilder.clearFields();

Loading diagram from json Object :

new Y.DiagramBuilder({
        fields : jsonData.nodes
        ,availableFields: availableFields
        ,boundingBox: '#diagram-builder-container'
        ,srcNode: '#diagramBuilder'
        ,render: true
        })

Now diagram is producing below shown error when trying to change position of node or connector :

showing error (1) : TypeError: instance.getConnector(...) is undefined
instance.getConnector(transition).setAttrs({

showing error (2) : TypeError: connector is undefined
if (connector.get('selected')) {

producing logical error (3): it is showing "properties name and type in setting" for existing and new nodes double (two times).

please suggest what i need to do here to make it error free: ?