Sounds like twaddle to me. In5 yrs on DH8 100/200/300 I never saw an inadvertant increase in thrust due to manipulation of the FMS.
As for torque rises with prop speed changes, climb Tq on the 200 is 114%, and at take-off power to set climb Tq of 114%, one only has to retard the condition levers to min (900 prop rpm).
An unsheduled autofeather on takeoff years ago resulted in the prop feathering with the engine still at takeoff power. The highest Tq I recall seeing was 125%. Engineer's checked their little magic book and after rectifying a faulty ECU connection, we were on our way. No Boro, no inspection, all within published limits.