Minor dashboard annoyance

Good day, all

Briefly, the CPU box on the dashboard either reads zero and is white, or 100 and is red, spoiling an otherwise-attractive presentation. There is no relation to the reality of the CPU load on the host.
This is happening on running on asterisk SVN-branch-1.2-r82334 on Ubuntu Server 6.06.2. Strangely, 'twas not always thus–it used to work just fine under 2.3.x, and then it started with the red stuff. It wasn’t clear what changed. I had hoped upgrading to would be the magic touch, but that didn’t do it.

Obviously, this is only a cosmetic problem (unless we start having CPU load issues) but I’d like to fix it. Can anyone recommend a place to look?