g1smd - 9:36 pm on Oct 20, 2012 (gmt 0)
Use the Live HTTP Headers extension for Firefox to investigate the request and the responses.
You appear to have an unwanted redirect that kicks in after the internal rewrite has occurred. This exposes the internal filepath back out on to the web as a new URL.
That's usually caused by having rules in the wrong order, or mixing directives from mod_rewrite and from mod_alias within the same site configuration.
Articles should not have a trailing slash. A URL with a trailing slash denotes a folder or the index page in a folder. Pages should not end with a slash.