Since the date is in the URL, you broke old links, and without a redirect at that. You should look into how you "republish" because it doesn't look like you're

Since the date is in the URL, you broke old links, and without a redirect at that. You should look into how you "republish" because it doesn't look like you're doing it ideally. Just some helpful advice. Without a redirect, SEO on the old post will go poof.