I've had a look at your page and it looks like the first time that URL is visited, the anchor is indeed dropped from the URL as you mention. However, if I paste the URL into the browser again, the anchor is retained and it works as intended. However, if I try again, it's dropped. It seems to work every 2nd time. I'm using Chrome to test. I'm wondering if there is something on your page or in your site that might be processing the URL?