I've just seen the bug when switching tabs in Firefox. As NeoAnimeHaven says, it seems to be new, otherwise I'm sure I'd have noticed it before. Some of the bugs NAH mentions do seem to have been fixed, at least for me.

A new one to me is that I got a message that I'm at the population limit when I tried to have a second baby. I therefore bought and built a third shack. However, when I tried to get them to kiss, I got the message about the population limit again! GRRRR!

I'd also mention that I've finished all the quests so far. Are there supposed to be more? There's also no indication on how the villagers are supposed to carry out research, or even what the benefits are. The same really goes for the other skills in the details screen; what's the faith one about, for instance?