Does anyone else have the same problem? Its a passive in def tree it says "3 sec inv on entering exposed state", but the buff is not applying i know atleast 2 people who tested it, still nothing.

one more thing, can you pls explain how this skill suppose to work? Lets say im at 25% hp the skill triggers, will 3 sec inv only last while im exposed or its guaranteed 3 sec inv? If ill brake exposed state, due to hp regen or healing, lets say 25,1% hp, will it expire? How often it can trigger once per 60 sec, once per mission?