Running on a Samsung Galaxy S4.

I unfortunately cannot reproduce this anymore, but in a world of mine created before 0.12, I had discovered an abandoned mineshaft but put off exploring it. I navigated back there after the 0.12.1 update and every time I got near the abandoned mineshaft, my game crashed. I reproduced this half a dozen times. I turned down the render distance, and was as a result able to get closer into the mineshaft, but the game would still crash. I then combined both turning on peaceful mode as well as turning down the draw distance, and I was able to enter the mineshaft: However, both of the mob spawners I found in the mineshaft afterwards were empty (Even after turning the difficulty back to hard), one empty spawner had flame particles surrounding it, one was just empty.

I haven't had any crashes since, but it was extremely reliable that when I got near the entrance to the abandoned mineshaft, my game would crash until I lowered the render distance and turned on peaceful mode: Sadly, I cannot reproduce it as I don't have the state of the game before the crashes stopped.