Quote Originally Posted by Johnist View Post
It is working as intended. A Critical is a Critical and most games do not differentiate between Critical + (heal) and Critical - (damage). It would require quite a bit of recoding (and an entire overhaul of the damage system) for a separation of Critical Heal and Critical Damage.
This is why he said a tool tip error in the OP. The Tooltip states: "Nullifies chance of suffering critical damage."