adding a new site based on another site

When I add a new site with a new language and select “based on site” and chose a site, I find some rather serious inconsistencies/problems:
1. Paths in the new site reflect the source site. For example: source site is site 4, (/wp-content/blogs.dir/4/files), new site is 10, but instead of /wp-content/blogs.dir/10/files I find /wp-content/blogs.dir/4/files.
2. If I go into settings and modify the paths, then the media library is non-functional because it still wants to look in the original site.
3. files, such as the media library are not copied to the new site folder… so I guess that’s why the path also points to the source site folders.

Is this expected behavior? Or what can I do to properly add a site?