404 doesn't work for missing Audio page?

When I go to a nonexistent audio page, instead of hitting a "404 page not found" with a corresponding 404 server code, it returns the Audio overview page, showing the most recent 10 audio uploads?

Why is this?

If I try and visit a nonexistent article or blog post on the same site, it returns the proper 404 server code, and visible 404 error page...