Crashing in 0.13.2

Sometimes when I'm playing on my kindle (5th gen) in 0.13.2, my screen will go black and will take me to my homepage. When I go back in my world, I'm right where I was in the game, but my progress that I just did deleted. This isn't a serious issue for me as it has only happened 4 times, but I'm worried if I build a huge detailed building and have that progress deleted. Please fix.