Redirect what to the canonical URL? The entire tag? Why, just to fix this HN submission? The proper solution here is to shoot an email to hn@ycombinator.com (which I've done).
Anyway, I didn't mean to argue. Have a nice evening :)
When there are two articles with the tag, they will both be shown on the 'publishing' page, in their entirety, newest first. See [1] for an example.
Redirecting would be akin to Google redirecting you to the current top result (like I'm feeling lucky, but for all searches)