Bug#333908: That's by design

["Wesley W. Terpstra" <wesley@terpstra.ca>]

Hi. Just wanted to let you know that REQUEST_URI is not supposed to  
be changed on rewrite.

From the apache docs:
	REQUEST_URI
	The resource requested in the HTTP request line. (In the example  
above, this would be "/index.html".)
The request line is not changed by rewrite, only redirect.

The purpose of that variable is to provide a CGI with access to the  
original request, before redirects.
If you need the location of the program after redirect, use SCRIPT_NAME.
If this isn't your program, report the bug to the author.