I've experienced two in- flight failures of the PT-6: a severed oil-line (EMB-110) and a failure in the interstage bleed valve which prevented engine acceleration from flight idle (SD-360).
If it can fail then it will. Whether powered by turbo- fan, turbo- jet, turbo-prop or rubber band the mathematics are inescapable. One minus one equals zero, down you go...... simple as that.