Every couple of days, the weight on both of the sites that I have showing network ads resets itself to 0. I log in, click validate and it instantly goes back to the weight it was before. Must be a bug.
It's a problem with the Google API. It returns 0 pages for a site every now and then, which results in a 0 weight even though you validate.
It's not every now and then, it's more like every other day. If I don't log in a couple times a day to make sure it hasn't happened I think I am losing all my ads in the network.