Jinin just has to hit you for the debuff to take place. It doesn't matter if he combos or not. I've had all my buffs stripped by Jinins multiple times. Also, even if you take into account this ability, Jinin still isn't good. Trust me, I've tried to build teams around him ( he was my second or third GNW rare). It takes very long for him to ac*ulate technique points and he needs 2 or 3 at least to deal good damage.