Vaadin notifications error in Eclipse

I’m experiencing now a repeating error in Eclipse:

An internal error occurred during: "Fetch all notifications".
org.json.simple.JSONObject cannot be cast to org.json.simple.JSONArray

As I understand it is somehow related to Vaadin notifications of “Vaadin plug-in for Eclipse”, but I have no clues on the source of this problem.

I have the same issue, anyone got the fixed for this?