Post Slug Edit Creating Duplicate Content Issues?

Hello everyone. I’m pretty new to blogging, and I am running into an issue that I’m not sure is a concern or not.

I had posted several posts and then at a later time when back and changed parts of post itself, the title, and the post slug.

After I made these changes, I hadn’t thought anything about it, until I listed my blog on Technorati. When I checked through the posts that were available from my site I noticed duplicate posts coming up in the results on pages 2-4, with different post slugs. Here is the example:

https://technorati.com/blogs/www.pseudorant.com?posts

My concern is that Technorati and other search engines like Google are seeing this as duplicate content? I have checked around and have not been able to find much information on this, like what causes it, how to correct it, and if it’s classified as duplicate content.

Since my blog is so new, I would like to do anything possible to avoid things that might hurt my ranking down the road. Has anyone run into this before? Is there a way to correct this by modifying a file or using a plugin?

Please any help is appreciated! I was directed here from the WordPress.com forums.