Water will flow under falling sand for a short amount of time.

What I expected to happen was...:
I didn't expect the water to flow under the falling sand, it did not happen in 1.4.2.

What actually happened was...:
Water was flowing next to a powered piston with a sand block on top and, when unpowered, the water flowed under the sand before it fell.

Steps to Reproduce:
1. Place a regular piston facing upwards on the ground.
2. Place sand on top of the piston
3. Place a redstone torch on the block under the piston
4. Place a repeater to power the block with the torch on it.
5. Add a line of redstone to power the repeater.
6. Add an enclosed water source block next to the extended arm of the piston.
7. Place a redstone torch at the end of the line of redstone to unpower the piston.
8. The water flows under the falling sand.