Has anyone had issues with this board and monitoring the Northbridge/Motherboard temperature?

I'm using Everest Ultimate to monitor temperatures, and every now and then (doesn't seem to matter if the comp is idling or fully loaded), Everest will lose the NB temp sensor. If I open up AI suite, it'll display something completely impossible like 190C. Touching the heatsink directly over the NB, it's warm, but not hot, I'd say somewhere around about 30-40C, and when Everest DOES report temperatures, it usually reads about 30-35C (and AI Suite will also agree with Everest's temps). Northbridge voltage in BIOS is set to 1.31v, and I'm using the 502 BIOS. I can't remember exactly, but I think the same thing also happened with the 107 BIOS.

Eller