301 redirect instead of 404 when URL is a prefix of a post or page name?
This is normal, it is because redirect_canonical(), which makes sure you are always at a “canonical” URL (conforming to your permalink structure), executes redirect_guess_404_permalink() to make a best guess at a post when the URL is incomplete. If you want to prevent this, I think the best way is to hook into the redirect_canonical filter, … Read more