The dates of the posts didn't get screwed up, those were the dates the spammers entered. As soon as someone posts an updated item in each forum, those dates will be negated.
I'm not sure why that's happening der, sometimes when you log in, it shows lots of new posts, and then when you click on one, it flags all the other new ones as old. Other times it doesn't flag anything at all. We're looking into it.
The entire codebase was rewritten to circumvent spam as a priority. That job is now done, so we need to refocus on the basics now too.