Cloning posts replaces original

Following the 3.5 update, whenever I clone a post it renames the original and replaces it with the cloned copy.

For example, the permalink for a live post called /original-post is renamed original-post-2, and the cloned post is now called original-post. But the edits in the cloned post appear on the live site as soon as I save a draft. I have to then retitle the original post by removing the -2 and update it. Only after the cloned post has a new permalink can I then go to the original post and reset the permalink to what it was before I cloned the post.

https://www.ads-software.com/extend/plugins/duplicate-post/