Ever since 1.12.0, the villagers in my worlds do not routinely close doors. They can always open them, but if the door is already open when they walk through, then they will not close it. Occasionally they open doors but don't close them. This opens the buildings up to be invaded by monsters and defeats the purpose of the doors. Please fix the Villager AI.

Edit: As of 1.14.60, this seems to have been resolved.