Last modified: 2012-10-13 02:49:33 UTC
When viewing a deleted revision of a page, the top message (MediaWiki:Undelete-revision) reads like "Deleted revision of PAGE ..." and the PAGE part is a blue link, even if the page is actually deleted. In the latter case, it should be a red link.
Actually, this is not a bug, because the blue link goes to Special:Undelete/PAGETITLE which is a special page, hence the blue link.