On my system (XP Pro SP3) they disappear after a few seconds when an application is closed.
When you see the discrepancy, does it come down to a realistic number after a period of time? (Obviously don’t initiate any processes during this time) Perhaps there is a process that is hogging a lot of CPU cycles slowing the time out down when you see this? (Maybe an AV update is happening or something?)
I noticed that a couple of days ago, attempted to terminate the incorrectly reported process within CIS, and then CIS crashed. I didn’t save the crash dump thought 88).