Then it's not IU's cache. If any of those values were greater than 0 then it would make sense as in that case users who are not logged in (i.e. ordinary website users) would see old (cached) page contents for some time.
Maybe you have some other form of cache on the server?
Can you make temporary administrator account and send me the login details via private message so I can check? Then, when I'm done, you can remove that account.