I see excellent new feature on development server to display multiple certificate chains if available. I have found one of our server that sends two certificates chains. First Certificate chain in my case is OK (also displayed in www.ssllabs.com test ) and second which is self signed certificate (it looks some internal web page for admin with self-signed certificate).
If I understand correctly if "Certificate #1" is with errors then at the bottom of web page "Why is my certificate not trusted?" section appears. But if "Certificate #1" is OK, but "Certificate #2" has some problems this section on bottom is not displayed, so that is probably the reason "Why" link becomes dead link.
By the way this server gets A+ grade. Is this fine? Looks like second certificate does not influence on grade at all.