I tested this above ground in a forest with a lot of lights. It would place 2 blocks instead of 1 every time. Then I went underground into a small room with no lighting. It always placed a single block. Also, in a superflat world with nothing in it, it will always place a single block.
I tested this above ground in a forest with a lot of lights. It would place 2 blocks instead of 1 every time. Then I went underground into a small room with no lighting. It always placed a single block. Also, in a superflat world with nothing in it, it will always place a single block.