When you execute the fill command wth the replace parameter, the southern-east block of the chunk is not removed. 

Create a new superflat world using desert preset and the seed 4317523603209072851 (It works also with others presets and seeds and coordinates)

Execute the follow commands:

/tp @s 38 64 -137

/fill ~-16 ~-16 ~-16 ~16 ~ ~16 minecraft:void_air replace minecraft:sand

/fill ~-16 ~-16 ~-16 ~16 ~ ~16 minecraft:void_air replace minecraft:sandstone

You'll notice that the block at 47, 55, -129 wasn't removed