Already posted about this issue in the comments, now my friend has it as well. In my case it was two weeks after the nuke. I was surviving in the countryside and suddenly died. When I respawned in Rosewood, there were somehow civillian and military NPCs around, some fighting taking place, as if the nuke hadn't yet happened and it was like day 3-4 of the first week, only with radiation present.

An hour ago a friend of mine who was surviving for a longer period of time got the same issue, only in Echo Creek. Ambulances get dispatched, civs walk around, but it's all post-nuke so it doesn't make any sense.

Probably a bug connected to character respawning after death in the same world?