Breaking twisting vines while crouching on them leaves you floating

What I expected to happen was...:
I accidentally broke the vines while I was fighting an Enderman and I would fall and it would kill me 

What actually happened was...:

It left me midair

Steps to Reproduce:

1. Climb twisting vines
2. Hold crouch
3. Break the vines

4. You stay in floating as long as you are crouching