Pounce - Predator's Mark is disabled in Abyssal Depths

Pretty frequently Predator's Mark seems to be disabled in Abyssal Depths - it does not apply no matter what the target is (rare, blue or white mob), with the only fix being unequipping and equipping the gem back. The only things that could influence it i can think of are that my pounce is lvl40, and i have "Close to the Surface" allocated.