Why does the following script generating xml output seem to make two requests in firebug?

The following code is an excerpt of a larger script to generate a Google review feed but simplified for the question at hand. It seems that when the node is added in the below Stub string it causes Firefox to make two requests. If <feed> is replace with something else FF makes a single request. I was wondering if this is normal, is there something I am missing that would correct this? Any insight on this would be helpful.

<%
Option Explicit
Dim Stub, OutputDoc
Stub = "<?xml version=""1.0"" encoding=""UTF-8""?><feed xmlns:vc=""http://ift.tt/REsXlC"" xmlns:xsi=""http://ift.tt/ra1lAU"" xsi:noNamespaceSchemaLocation=""http://ift.tt/1szsfnc""><publisher><name>Sample Retailer</name><favicon>http://ift.tt/11JT8Mu;"

Set OutputDoc  = Server.CreateObject("MSXML2.DOMDocument.3.0")
OutputDoc.loadXML Stub
Response.ContentType = "text/xml; charset=UTF-8"
OutputDoc.save Response

%>