power is rpm times torque.
When the blade is feathered its zero torque. Its measured by the twisting moment applied against the mounting ring. But I don't think the blade can travel that fast to be honest and just from the torque values you can't really tell where the prop angle is you normally get negative torque when the props are disked as fine as they can get when shutting the power levers at Vmo and the flight idle is set to low. I can't see the blades going to fine then to feathered then back to fine again it would require a huge flow of oil and pressure.
The temperature torque limiting system is a fuel dump valve and it will drop your torque from 100% down to 40% in 0.5 of second. And its normal for the rpm to drop until the prop pitch controller sorts the blades out and restores the rpm.
I will see what diagrams I can find at work this afternoon for the engine prop combination.