What exactly is the % “chance when struck” on the Versed in Stone grandmaster trait (Revenant Retribution line: https://wiki.guildwars2.com/wiki/Versed_in_Stone)? With basically any other trait in the game with a “chance on struck” clause, the tooltip tells you what the % chance is. This one does not. Is it a 100% chance to trigger when you drop below 50% health, or some other % chance that’s not stated?
Answer greatly appreciated. Thanks!