Phone Screen Becomes Unresponsive After Putting Phone To Sleep With App Running

Whenever I put my phone to sleep/lock it with Minecraft running then unlock my phone, the bottom half of my screen turns black, the app looks like it is trying to run in portrait orientation instead of landscape orientation, and the screen is unresponsive. However, I can still use the app switching button but the screen is still unresponsive and the blackened bottom half of my screen is still there. The only way to recover the use of my phone is to restart it.