I created a brand new world in Debug mode and messed around. Then I saw the chests and "experimented" with one by putting an item in.
What I expected to happen was the item i put in the chest (Piston) would pop out when I broke it and the chest would replace itself.
What actually happened was the game crashed.
Steps to Reproduce
1. Create a new Debug world.
2. Find the chests.
3. Put any item (I believe, or else a piston) into one of them.
4. Break the chest.