Passenger villagers exit boats upon world loading

Once loading a world where a villager is in the passenger seat of a boat, the villager will be out of the boat, and requires to be replaced back into it.

How to recreate:

1. Get a villager in the back seat of a boat.
2. Re-log.
3. The villager will be out of the boat.

What's meant to happen: 

Villager remains in boat