If this bb (or any other that relies on cgi scripts/cookies/caching), for example, goes down while you have it open in your browser, then when it comes back you are going to see it as it was THE LAST TIME YOU OPENED IT. That could have been 10 minutes before it went down, 10 hours before it went down.
If you then close your browser, re-open it, re-open this board and refresh, it will be up to date.