Sudden engine failure

Several times now, both before SU12 and after, I have a perfectly uneventful flight and then on approach, having gradually reduced speed and height, I reduce the collective slightly to increase descent and then without any other input all goes haywire and engine failure. I have it set at medium with auto governor which I’ve always been happy with. I will continue to monitor closely to try and interpret the throttle/ rotor speed at point of failure but can anyone give some advice please.

Which heli is this in, and do you get any message indicating the failure type?

Sorry thought I was posting on B47 specific hence no mention. This was not a software glitch as such so no message. As said an apparent engine failure. Cyclic juddering like mad. Since done 3 careful approaches with repeated screen shots in case I could identify precise state at point of failure but no recurrence. Did try to ensure man pressure stayed up and rotor speed. Continuing to monitor.