Tooltip for newly nerfed Limited Invulnerability Potion = " Use: Reduces physical damage taken by 120 for 8 sec. (2 Min Cooldown)"
Tested this by rounding up a bunch of mobs hitting me for 90 damage, popped a LIP and they started doing 60 damage when they should do zero damage.
If this is not a bug then the potion is 100% useless for everyone at all levels.