Playing the game normally and hitting the power button to put the tablet in standby. When the power button is pressed to resume playing, the game is completely unresponsive. Hitting the home button, then bringing up your open apps and removing MCPE (essentially forcing it to quit) and re-opening the game will result in being back at the title and being playable again.

Motorola Xoom FE on ICS 4.0.4 and Nexus 7 2012 on KitKat latest build.