I have a feeling someone renamed "Shopping by Country" to "Denmark" and it errored for some reason, leaving the page in limbo. The "Shopping by Country" URL points to a certain article ID. When VaultWiki looks up the article with that ID, it sees "Denmark", and forwards the user to the correct URL. This is different from a wiki redirect, which doesn't use HTTP redirects for logged in users, and is more a way of defining synonyms for articles rather than showing that the article moved.
Unfortunately as this error probably occurred some time ago we don't know why the article is now missing -- the history for what is now "Denmark" may or may not exist anymore. To get back at least the current version, go to AdminCP > VaultWiki > Namespace Manager. Next to Category, click [Rebuild].