Indeed there was a lesson learned in all this for all manufacturers not just RR
I submit that for some, this was a painful re-learning of an old lesson.
Turboshaft/turboprop designers learned long ago they must design for the loss-of-load case - shaft or gear failure, loss of a prop, etc. Turbine overspeed can occur very very rapidly in this case, and active overspeed protective systems are commonly employed to protect the aircraft.