What I expected to happen was...:
Hostile mobs would not notice me

What actually happened was...:
I got rushed by Zombie Pigmen

Steps to Reproduce:
1. Spawn/find hostile mobs
2. Use invisibility potion
3. Come within mobs normal visual radius

Also in re-testing this bug I discovered 2 others
1: Drinking a potion in survival gives you a water bottle instead of a glass bottle
2: Armor on skeletons does not match their viewmodels