I'm having a problem that's not quite the same, but falls under the same scenario. I left my game with nothing building somewhere around 88/90 pop. At some point today the population rose to 92/90.

Not sure why it rose unless your pop just continues to rise on its own, which I don't think is the case.

Is this still happening?

Units also occupy housing, Koldunk. Do you have any?

I haven't had this problem for a while now and may have been a result from me sending units on raids. It still doesn't quite add up, considering the amount of troops I had then, but it may still be the result of my misunderstanding of game mechanics.