Links to attachments from within comments work in preview and wysiwyg, but not when saved and displayed

If you link to an attachment from inside a comment, the link works in the preview and in the Rich Text editor. It doesn't work once the page is saved and you're viewing the comment. The results are the same whether you create the link manually from within the Wiki Markup editor or whether you use the link builder to create the link.

Steps to reproduce:

1. Find a page that has at least one attachment and which allows comments. It doesn't matter whether it's a page or blog post.
2. Add a comment
3. Try to link to an attachment by selecting "Search" or "Insert Web Link" from the menu and then changing to the "Attachment" view on the popup that appears
4. Link to an attachment
5. Preview your comment and view it in the Rich Text editor
6. Save your comment
7. The wiki markup will appear in red text