Gee....
Did the hot section shell or the gearbox explode? Over-TQ comes to mind. Poor maintenance a likely reason too. Operators on the pinch like to run PT6 engines way past the maint. sched. Sure it wasn't just an FCU shaft fail?
Design fail in this engine, in all likelyhood, is out of the question. All but impossible, but still possible. Could be FOD through the compressor. Nine chances out of ten it's poor maintenance or pilot engine control error or abuse.
I am interested in knowing when info becomes available.