The Sandbox release has broken the Direct Post 2.0 functionality.
The PublicHostedPageLite.do responds with a JSON instead of putting on the response header a location with the callback result.
The JSON body from PublicHostedPageLite.do contains:
"{\"redirectUrl\":\"https://www.\",\"captchaSiteKey\":null,\"success\":\"false\",\"errorMessage\":......}"
The value of "redirectUrl" should be placed on header not on the response body!