Revision isn’t overwriting original post URL

I created a revision of this post https://www.cottercrunch.com/anti-inflammatory-gluten-free-meal-plan/ and drafted my new article in it.

When I hit publish on it this morning, it published with this URL https://www.cottercrunch.com/anti-inflammatory-gluten-free-meal-plan-clone/ and the old post is still on my site with its original URL of https://www.cottercrunch.com/anti-inflammatory-gluten-free-meal-plan/

Why is this happening? The only way I can think to fix this now is to paste the NEW content directly into the existing (old) post, but then I’ll have duplicate content in my RSS feed (once with the cloned URL and once with the original URL)

The page I need help with: [log in to see the link]