I have this issue with pretty much all major pages - categories, tags, author, etc. Anonymous users get served a week old page.
I have the option for "cache rebuild" (serves anonymous users a cached page while building a new one) checked. It does not happen.
For the homepage, I actually added a function to clear its cache whenever it is updated. I couldn't allow it to remain cached.
I am now thinking that I will have no alternative but to write a function that clears out the cached file for every category/tag/author/taxonomy of a post when it is published/updated, which is quite cumbersome.
But I have no idea how to solve this another way, and it is a rather acute problem.
I would appreciate getting some guidance here.
Thanks :)
Bira