Villagers stop having schedules when I open my world the second and later times

When I open my new world and go to a village, there's the typical thing I see in a village; villagers working, gathering, restocking and sleeping. When I saved and quitted my world and came back in again, the villagers were just wandering and not doing anything. I can still trade with them, but they never restock. I tried building a golem farm, but because they weren't sleeping, it failed.