When powering an iron door with a single redstone, a block inbetween, and a button, a door normally is powered, and is in this version of Minecraft. However, if a barrel is placed in front of the single piece of redstone, directly below the button's Z coordinate, and the world is exited and relaunched, the door no longer opens with the click of the button. If the barrel is placed below the button in the exact same manner and the world is not exited, the redstone successfully powers and opens the iron door.

*The video provided is cropped to fit the maximum file size requirement, however, when replacing the barrel with any other block and reloading the world, the door still opens.