valid_referers directive not working correctly

[justin]

Very strange, moving the directive into the server block, now blocks
everything, including requests from my own server.

 valid_referers server_names *.my-domain.io;
 if ($invalid_referer) {
    return 403;
 }

Strange that when the code was copied twice into the / location bllock and
php match block it worked.

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,232722,232727#msg-232727