Response body is empty for some sites FiddlerCore

Question

I'm doing some test with Fiddler core and I'm able to intercept the traffic for almost all sites, but for some HTTPS sites I get empty response body.

I have found 2 sites by now:

Facebook.com Google.com

I have tested other HTTPS sites (including StackOverflow) and I have no problem with them.

This is my code:

var content = oSession.ResponseHeaders.FirstOrDefault(
    (item => string.Equals(item.Name, "content-type", StringComparison.InvariantCultureIgnoreCase)));

if (oSession.host.Contains("google.com"))
    if (content != null)
    {
        if (!content.Value.Contains("text/html")) return;
    }
    else return;
else return;
var x = oSession.oResponse;
var body = oSession.GetResponseBodyAsString(); // actual response from the server
var doc = new HtmlDocument();
doc.LoadHtml(body);
var htmlNode = doc.DocumentNode.ChildNodes["html"];
if (htmlNode == null)
{
    return; // no HTML tag -> not an HTML page
}

As you can see I get the content-type header, then check if the session is from Google and then check if the header value is text/html, if it is then I put the response body in the body variable...

At this point I put a break point to verify the body value but it is empty (""), beside that when I continue the execution the Google home page load anyways, and if I check the session with Fiddler I can see the response body normally.

I have looked in Google and found nothing, also I have checked every response from Google (not only text/HTML) and found nothing that can help.