DSXchange

When I view posts in DSXchange using Internet Explorer or Firefox the "unread" (orange) icon changes to "read" (blue).

But, when I use Safari as my browser, they remain "unread", which makes life difficult.

I have experienced the same.
If I launch the website using www prefixed to the site name, all is well; If I go directly to dsxchange.com I have the same issue.

That's the answer. With "www" in the URL it works. Without "www" I get the behaviour I described. No idea why - some weirdness in the PHP that the site runs, I suspect.