Villagers leave doors open.

Villagers are often leaving the door open, which makes it difficult because they leave the villagers more exposed, helping the zombies to kill them.
An extra bug is that when many villagers try to open the door, a bug, not very frequent, happens in the door, it gets the sound of opening and closing all the time every second.
Sorry for the English, used google translator a bit for help, since I am from Brazil.