We have a MU install with latest version super cache installed. We have a client that was getting 10 to 20 second page load times on his site or any site on our MU install. We were unable to reproduce the error, our page load times were fine in our tests and no other users reported having the same issue.
We then noticed that the same client could access our static sites not on our MU install with no issues.
On a lark I disabled WP Super Cache and deleted our cache and the client's page load issues went away. We haven't had a chance to test if they still have an issue after we have reinstalled super cache yet...
Anyone have any feedback on why one specific user or locale might have this sort of issue with cached pages? Any feedback appreciated.