my horse disapeared when i got off of it and villagers disappear when they leave a mincart

Put the summary of the bug you're having here

What I expected to happen was...:
the horse and villager wouldn't disappear

What actually happened was...:

my horse and villager disappeared

Steps to Reproduce:
1. put villager in minecart
2. use sword to break minecart that villager is in
3. watch it disappear