Facebook bugs? 1) user picture url 2) authentication with cookie
===

I have a Facebook canvas application written on asp.net mvc. I can't see what's going on in facebook.

1.  I have client-side code that loads FB user picture:

    FB.api('/' + userId, { fields: "id,link,name,picture" }, function (user) {  
                $('img[data-fb-user-img]', subjectVoterElement).attr('src', user.picture.data.url);  
            });

One day it responds picture url in user.picture, another day - in user.picture.data.url so i have errors time to time. Why FB gives different respond structure?  
2.  
To authorize FB user in my app i use facebook cookie being sent to my app server. Then i extract value from it, then parse the value with ParseSignedRequest method and exchange obtained code into token.  
HttpCookie fbCookie = filterContext.RequestContext.HttpContext.Request.Cookies[
String.Format("fbsr_{0}", System.Configuration.ConfigurationManager.AppSettings["FB_Id"])];  
                string code =
                    ((dynamic) FacebookService.FacebookService.Client.ParseSignedRequest(fbCookie.Value)).code;  

                using (var webClient = new WebClient())  
                {  
                    var result = webClient.DownloadString(  
                        String.Format(  
                            "https://graph.facebook.com/oauth/access_token?client_id={0}&redirect_uri=&client_secret={1}&code={2}",  
                            FacebookService.FacebookService.Client.AppId,  
                            FacebookService.FacebookService.Client.AppSecret,  
                            code  
                            )  
                        );  
  
Sometimes i get authorization error saying the code is expired or specified user has logged off from facebook. In fact, i logged off a hour ago and since that moment this have already been worked successfull. Also, the facebook cookie expiration time is set long enough and hasnt come yet.  
Does anyone have the same problem? Thanks

