Sand floats above snow layer

When sand is placed above a snow layer, it does not fall and simply remains in place floating. The block of sand should not float and should replace the snow layer.

To reproduce:

1. Find a snow biome (idk if it works in creative with placed snow yet)
2. Place a 2 tall pillar next to a layer of snow using any block.
3. Place a block of sand on the highest block of the pillar above the snow layer.
4. Observe that the block of sand remains in place, floating above the layer of snow.