Search Query error….or not?

Hello Everyone,
I’m using WP version 2.6.5

I’ve been using WP for a while now, and I’ve gotten pretty familiar with it. But today I noticed something weird and would like to know if that is normal or if there is an error in my codex or database.

I made some changes to the content of an old post that was published few weeks ago, and saved the post again. when I type in the permanent link for the post and visit it directly then everything looks normal. All the changes are published and everything looks fine.
Normal permanent link: https://www.futbolwallpapers.com/team_wallpapers/ac-milan-wallpaper-1/

But when I perform a search on my live site for that post then I see a the original post as well as a duplicate of the same post in the search results, where the duplicate has a different category and permanent link.
The category for the duplicate is “Uncategorized” and the permanent link is: https://www.futbolwallpapers.com/uncategorized/8-revision/

I’ve never noticed this before, and was wondering if this is something normal or if it is an error in my codex and/or database.

Thank you in advance.