When you place a second chest down next to another chest to create a double chest that is also surrounded by more chest it creates a lighting glitch.

I expected that the chests wouldn't go all dark

Once i placed the chest the chest in between the other two chests most of the chests that were against the wall had become dark .

Steps to Reproduce:
1. First Put chests down leaving only a one block in between
2. Then but a chest in between the the two chests