Splash Potions not affecting Skeletons

What I expected to happen was...: the skeleton(s) should have taken damage from Splash Potions of Damage. Instead, nothing happened.

What actually happened was...: the splash potions made the splash effect and injured me, but nothing happened to the skeleton(s).

Steps to Reproduce:
Creative Mode:
1. Spawn a skeleton.
2. Throw a splash potion.
3. Observe as nothing happens.

Survival Mode:
1. Find a skeleton.
2. Throw a splash potion.
3. Observe as nothing happens.