Having operated PT-6 powered airplanes in the mid-sixties, some folks ignored the torque limitations.
It got quite expensive.
Greatly increased propellor reduction gear wear and, even worse, greatly increased power turbine wear...so much so, that on one engine I noticed, while it was in for overhaul, fully one fifth of the power turbine blades had been worn away...gone.
P&W Canada provided a circular power computer with each engine type, and its use was mandated by aircraft operators.
To ignore torque limitations with a turboshaft engine is foolhardy in the extreme.