I had an old world from 0.6.0 that had an automatic cactus farm on it and when I updated he game and played that world the cactus would grow right next to the block still.

What I expected to happen was...
The cactus block was supposed to automatically be destroyed and the cactus block item was supposed to be dropped.

What actually happened was...
The block ended up growing right alongside the other blocks

Steps to Reproduce:
1. Place a block of sand on the ground and the. Place a cactus block next to it.
2. Then wait for the cactus to grow. Once it has grown tap the side of the block with a different block, e.g. Cobblestone.
3. Then wait for it to grow again and you will see that it still grows.