Nether sprouts don't break when the block beneath them is broken

Nether Sprouts do not break when the block beneath them is broken

What I expected to happen was...:
I thought that the Nether Sprout would break

What actually happened was...:
The Nether Sprout is not breaking it just floats

Steps to Reproduce:
1. Find Nether Sprouts
2. Destroy the block beneath them