It does show on the tab for me for both pages. When you have a problem with one particular site, a good "first thing to try" is clearing your Firefox cache and deleting your saved cookies for the site. This can resolve issues with mismatched files that sometimes occurs during development.

(1) Bypass Firefox's Cache

Use Ctrl+Shift+r to reload the page fresh from the server.

Alternately, you also can clear Firefox's cache completely using:

orange Firefox button (or Tools menu) > Options > Advanced

On the Network mini-tab > Cached Web Content : "Clear Now"

If you have a large hard drive, this might take a few minutes.

(2) Remove the site's cookies (save any pending work first). While viewing a page on the site:

• right-click and choose View Page Info > Security > "View Cookies"
• Alt+t (open the classic Tools menu) > Page Info > Security > "View Cookies"

In the dialog that opens, you can remove the site's cookies individually.

Then try reloading the page. Does that help?

Whoops, I was visiting with scripts disabled. If I enable JavaScript, then I see what you see. Hmmm, why would that be?

(It's not inherent in using hash marks in URLs: http://www.jeffersonscher.com/ttw/201.../#alb2016)

the url with hash mark works fine in ie and Chrome

The problem seems to arise from the scripts hosted on ajax.microsoft.com. If I block those, the favicon loads. I notice in those scripts a few places in which Firefox is treated differently than other browsers. However, I don't know the significance of these differences:

Sys._Application.prototype.get_stateString=function(){
 var a=null;
 if(Sys.Browser.agent===Sys.Browser.Firefox){
  var c=window.location.href,b=c.indexOf("#");
  if(b!==-1)a=c.substring(b+1);
  else a="";
  return a
 }
 else a=window.location.hash;
 if(a.length>0&&a.charAt(0)==="#")a=a.substring(1);
 return a
};

Sys._Application.prototype._raiseNavigate=function(){
 var d=this._historyPointIsNew,c=this.get_events().getHandler("navigate"),b={};
 for(var a in this._state)if(a!=="__s")b[a]=this._state[a];
 var e=new Sys.HistoryEventArgs(b);
 if(c)c(this,e);
 if(!d){
  var f;
  try{
   if(Sys.Browser.agent===Sys.Browser.Firefox&&window.location.hash&&(!window.frameElement||window.top.location.hash))Sys.Browser.version<3.5?window.history.go(0):(location.hash=this.get_stateString())
  }
  catch(g){}
 }
};