Why is application instantiated twice with XS addon?

HI,

I have a Vaadin app (6.8.12) that works fine with standard application servlet(com.vaadin.terminal.gwt.server.ApplicationServlet) but fails when used as a cross site app using th XS addon servlet (com.vaadin.addons.xs.server.XSApplicationServlet).

With the XS addon, the application is getting created twice! The parameters passed via the URL are only available in the first instance and since it is replaced by the second instance(which is invoked by a UIDL request) the params are not there and the app fails.
Why?
Is there a solution?

Thanks,