Using /summon command in a creative world to summon a villager with a minecart on top of it. In my first attempt, the game crashed immediately with no crash report provided. The second attempt after restarting worked but the mob behaved strangely.

While idle, the villager slowly moved in one direction; it looked similar to the behavior of a minecart while riding another minecart and colliding with an entity to cause the minecarts to bump into each other creating perpetual motion.

The command used was:

/summon MinecartRideable ~ ~ ~ {Riding:{id:Villager}}

about a minute later of observing its behavior, the game crashed and I was presented with the provided crash report.

My player name has been omitted as i don't feel it is of any importance to the issue. I'd like to keep that private if that's alright.