Zombie Pigman crashes the game when teleporting to Overworld.

Device: Xiaomi Redmi 1S 1.6GHz Quad-Core 1GB RAM

I've created a Nether Portal and let it on forever, After a few while, I heard an Oink! sound. (It's like he got suffocated or something, There is no blocks blocking the Nether Portal entrance) and then the game crashes. Please Confirm & Fix.. Thanks!