Falling sand breaks if a solid block is pushed into its space

Normally we'd be able to make sand bridges with pistons pushhing up multiple blocks of sand. You push sand up and just before the block falls you push another block under it and-so-on. But since snapshot 13w01b sand is falling so quickly it breaks when you push another block of sand under it (even with perfect timing).

What I expected to happen was...:
Sand block pushed under the lifted sand block (just before it falls) succesfully (like it used to before this snapshot)

What actually happened was...:
Sand block pushed under the lifted sand-block breaks the sandblock.

Steps to Reproduce:
1. create a piston setup where one piston will push a block of sand up, and just when the piston retracts make another piston push a block of sand underneath before the block falls, this was possible before 13w01b.