Comment 11 for bug 122602

This bug seems to be related to the package "xdg-user-dirs". The bug first occured when i've installed this package. When you deinstall the package and recreate another user, the bug does not occur.
For your normal user, you have to logout, delete all gnome-related directories (i know this is a brutal method, but i haven't found another working solution) and than login again.
Now all the duplicate entries should have gone away.