This is an old bug that has resurfaced from 1.13 and was tracked and promptly squashed. MCPE-53168.
The way to recreate it is by having one player stand on a shulker box with another player nearby, and open it. It doesn't crash the game every single time, but if done repetitvely it can crash the game. Found and tested on a minecraft realm, crashed my mobile and xbox friend's game.

Small note: my xbox friend said he saw me fly off at high speed when i opened it and came back near instantly, and later saw my fly off without returning, causing me to be invisible, which was followed immediately by a crash.