Our Border Manager is used as our HTTP proxy, and all users get to the
Internet via the proxy server.

More and more regular, we are having to unload Proxy and reload with -cc to
clear the cache, just so some sites load correctly.
If I bypass the proxy and setup a filter to allow my machine out directly to
the Internet, all is fine, but as soon as I start using the proxy again,
sites keep hanging, are slow to load, and particularly those with cookies
and/or login sessions are timing out or not logging in at all.