Board Thread:Questions and Answers/@comment-28892370-20161029003927/@comment-28905095-20161030001210

In this official bug report, see https://bugs.mojang.com/browse/MCPE-17695, they state that it seems like there has been a memory glitch in 0.16 which especially targets older devices with not so much online RAM.

In other words, freeing up general storage will not help, but if possible freeing up the number of loaded applications and services might help. This is also why reducing rendering and lowering graphic quality helps (to some extent for some), as they reduce the demand on RAM.