When changing forum language in usercp to another language, let say this example:

Now: english
Changing for french
Changing back to english

When saved, the browser URL keeps adding the old lang=fr at the end or any URL's (or in this case, here on your forum, it keeps this: http://www.vbenterprisetranslator.co.../fr/usercp.php

Is this a bug?

BTW why is it different here? Here we get forum/fr and on my forum we get lang=fr at the end of URL'S?