One category of posts displays index instead?

After installing a plugin or two which I’ve now removed, one particular category of posts is failing to display the actual post any more, but instead the homepage or another category page.

It’s really strange..

Here is a link to a page that is doing this: http://www.top5best4you.com/reviews/dirt-devil-scorpion-quick-flip-handheld-vacuum-review/

That’s a single post, under the category reivew but showing the index. I need to fix it ASAP. Please help.

No theme files have been changed.

Thanks