Attachments are being indexed

WordPress version: 3.5.1
WordPress SEO version: 1.4.7

I did this: I checked redirect attachment urls to parent post url

I expected the plugin to do this: no index attachments

Instead it did this: attachments are indexed and cached.
For example this attachment is both indexed and cached
For example this is the indexed version
This is the cached version (for some reason it doesn’t even include the image even though that is the only thing it was supposed to cache)

http://wordpress.org/extend/plugins/wordpress-seo/