I built a 64 block pillar and spawned on them. Then I died and I respawned on the pillar, and I immediately threw myself down, but I didn't die (see video at 0:18)

What I expected to happen was...: 
Dead

What actually happened was...: 
Don't even take a heart of damage

Steps to Reproduce:
make a 64 block pillar, the set the spawnpoint on the top then die adn when respawned continue pressing W + RUNCOMMAND(ctrl) + space