Gravel tower floating when I put a torch under it

Put the summary of the bug you're having here

What I expected to happen was...:
The gravel blocks to fall when I put the torch under it.

What actually happened was...:
The gravel just floated on the top of the torch

Steps to Reproduce:
1. Build a 1x1 gravel tower
2. Break the block on the ground with a torch equipped
3. Immediately when it breaks, right click so you place the torch. 

4. it should be floating