I've tried a 6.0.1 CF1 Admin client against a 6.0.2 CF1 server (admittedly, not your combination), and the utilisation appears fine.
So it could still be a bug in your particular client or server version...
But here's another line of inquiry. Do you have platform statistics enabled. I believe it should now be standard in 6.0.x and later 5.0.x releases. But I guess it could be turned off. There's some info in this article on server health monitoring (but platform stats are actually independent of health monitoring).
http://www-10.lotus.com/ldd/today.nsf/62f62847467a8f78052568a80055b380/453d9e87c12cda0800256bce003f3c6e?OpenDocument
The posting say you're running Windows 2003. Another possibility is that Domino somehow can't get CPU utilisation on 2003 Server.
Yes, I am kind of grasping at straws now!
Rupert