I just enabled Failed Request Tracing for a site and I get a URL_CHANGED event as the third item on the log.
1. GENERAL_REQUEST_START SiteId="1", AppPoolId="DefaultAppPool", ConnId="1610613013", RawConnId="0", RequestURL="http://example.com:80/test/wp-admin/", RequestVerb="GET" 15:35:54.176
2. GENERAL_SET_REQUEST_HEADER HeaderName="AspFilterSessionId", HeaderValue="", Replace="true" 15:35:54.192
3. URL_CHANGED OldUrl="/test/wp-admin/", NewUrl="/index.php/test/wp-admin/" 15:35:54.192
4. GENERAL_REQUEST_HEADERS [...]
5. GENERAL_GET_URL_METADATA [...]
6. URL_REWRITE_START [...]
Can someone tell me where the URL_CHANGED event comes from and how I can prevent it?
Update: The "default document" is set to "index.php" on our server. Could it be that the server automatically appends index.php to a path if the path does not specify a proper file or folder? I tried removing all "default document" entries but this didn't change the behavior...
Update2: I am still looking for an answer to this question... ;-)