When the torque limiter is worn, you will damage the belts. Upgrading to the 900# spring and the new style thrust bearing will help extend the life of the belt. Make sure there are no grooves in the cam.
If the torque limiter is updated and in good shape, you may just be pulling the belt that hard. Some years are like that.
Another way to know the limiter is acting up is loosing rotor RPM's without really pulling down the motor, or somtimes the engine just falls on it's face when you hit a tough spot.