Happened to me too .But i don't think google uses pingomatic to ping websites . You used pingomatic isn't ?
It's either a good thing or a bad thing, either they're starting to ping for us or they have screwed something up.
Well , do you have the option turned on in blogger to ping weblogs.com ? Pingomatic grabs that list periodically and goes through it I think. So it is a matter of timing if you beat that polling or not.