[Plugin: Redirection] Issues with Categories

I’m having an issue where my WP categories are re-directing to individual posts or 404 pages. I haven’t made any changes to my categories or link structure lately, but I have been fixing a lot of 404 errors that developed when I removed tags from my site.

Could this be something to do with the Redirection plugin? I have checked to ensure I haven’t accidentally re-directed a category url to a page, and can’t find evidence of that.

Any advice appreciated!

http://ww.wp.xz.cn/extend/plugins/redirection/