If you are needing Full Left Pedal to counteract Hover Torque and you reduce the Throttle...along with reducing Torque you also reduce the efficiency of the Tail Rotor as the RPM drops. Question for you is which reduces quicker....the Torque or the counter torque force?
If the tail rotor thrust decreases quicker than the Torque decreases....you would have a bigger problem than before you went rolling off the Throttle.