I'm pretty sure it syncs with apples time servers if you leave wifi on...kind of like how cell phones do the same thing. I always have wifi on so if there is a problem with the hardware clock I wouldn't know about it...
Not sure if you noticed the post above yours, but my wifi was on. 🙂 I can't be more plain than that. I have no reason to turn it off.
I'm not sure if it's only happening to some of us, or needs very specific conditions to happen, but I'm sure more people will start to notice and Apple will deal with it. It's not a huge worry for me.