MCPE Closes while on Realms

While playing on Realms, sometimes immediately after the terrain loads, my MCPE client abruptly closes with no warning. When it happens during gameplay, I usually experience tremendous lag while placing/destroying blocks or opening chests.

The phone I'm using is a ZTE Warp 7 (http://www.phonearena.com/phones/ZTE-Warp-7_id10207)

The MCPE version that shows on my screen is 1.0.2 and on the Google Play store it shows as 1.0.2.1, updated January 19, 2017. I do not see the 1.0.3 that the "Affected Versions" menu has.

I don't know if it has to do with the world file size, but that's 167.5MB.