phranque - 11:12 pm on Sep 6, 2012 (gmt 0)

if you request /index.php, for example, from the old server it will take two 301 responses before you get the Location: header containing the canonical url.

you can fix this in the .htaccess file on the old server without touching any php code because the request will be handled with a redirect by apache and the php script on the old server will never "know" it happened.