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When I go to a Stack Exchange page (especially Stack Overflow), sometimes it will display a notification bar on top saying: 'click on "xxxxx" user id, and refresh the page'. Once the user clicks that link, we have then logged in again.
I am a little bit confused. Since the page had already shown my user id on the notification bar, I assume the Stack Exchange server has probably found my session. Why does it require me to refresh it again?
My little guess is the Stack Exchange server did find my session, but my session is almost expired, so it gives me a notification to prolong the session again.