The locked chest (as it now holds no information) can be pushed by a piston, and if you stand in the way of it as if you are creating an x-ray machine, it will crash the game as it intersects your head.
Steps to Reproduce:
1. Place a piston with a locked chest (id: 95) in front of it
2. . Place a lever with redstone leading to the piston
3. . Dig a hole in front of the locked chest's path
4. Jump in the hole and push the lever
Duplicate of MC-12984, please use the search function to see if your bug has already been submitted. Currently over 56% of tickets are being closed as duplicate.