Right now, I'm not having any trouble with the posts I've read turning red again, but this seems to happen when my IE history cache gets full. The only way I know to fix this is to click "Clear History" under "Internet Options" in the Tools menu. This does rather defeat the purpose of having a browser history in the first place, but Microsoft's programmers have a lot of trouble dealing with out-of-resource situations. So if nothing else helps, try "Clear History".