Villagers

Open and close doors continuously, failing to accomplish their goal of getting in or out, when a door is blocked from either the inside or the outside of a house.
Note: Bug reproduces more rarely when a villager is outside the house.

Baby Villagers ¹

Ignore or don't enter houses with doors blocked by the upper or lower half at nighttime, even if they're small enough to go inside. But if the top half of a door is blocked, sometimes they do go inside, but less frequently than unblocked doors at nighttime. Seemingly as frequent as when villagers enter unblocked doors at daytime. Also, when they decide to enter, they walk slowly towards the house to enter it, just like at daytime.

Baby Zombies ²

Don't break doors that are blocked by the lower half.

¹ To reproduce (baby villager)

1. Build a house with a door
2. Block the lower half or the top half of the door
3. Summon baby villager outside the house

   /summon Villager ~ ~1 ~ {Age:-6000}

4. Set time to night to more easily see the bug

   /time set night

5. Observe the issue

² To reproduce (baby zombie):

1. Build a house with a door
2. Block the lower half of the door
3. Summon baby zombie that can break doors outside the house

   /summon Zombie ~ ~ ~ {IsBaby:1,CanBreakDoors:1}

4. Go inside the house with survival mode
5. Observe the issue