Ok, do you have firefox? Grab it, and install the livehttpheaders extension. This thng is an absolute treat and makes it easy to see where your browser is going.
http://livehttpheaders.mozdev.org/ Between that and your regular access logs you might be able to figure out what is really happening here, and then perhaps, why.
And if not... well, you learned something <img src="https://www.ubbcentral.com/boards/images/graemlins/laugh.gif" alt="" />