Oh, I should've searched first. And no save game – I didn't suspect this being an actual bug. I will save if this happens again.
This happened when I saw a wolfpack nearby a village, just few tiles away. I lured them passively towards the village in zoomed in map in hopes that the villagers would help me take down some. They were however totally passively towards the wolves. I did some testing aggravating the wolves with arrows and when they turned hostile, villagers remained passive. The wolves didn't attack them. I actually went hiding to a house and a villager opened the door for the wolf to come in
When they calmed down I left. A day or two later I came back to the scene in the image above.