WordPress Pagination – 301 Redirect Issue

Are your /old-article/ and /new-article/ posts both separate WordPress posts? If they are separate (published) posts, and all you’ve done is redirect /old-article/ to /new-article/, then as far as WordPress knows, both posts are still published in the backend, therefore both /old-article/ and /new-article/ will show in the blog feed, regardless of the redirects. You have to draft or delete your /old-article/, OR change the permalink on /old-article/ to /new-article/. Otherwise, it will still show in your blog feed.