TheDoctorMedic has produced a good objective review of the accident examining possible causes:
Of note are the parallels he identified with the loss of the Air Evac Lifeteam Bell 206L-1 N114AE in Manchester, Kentucky in 2013 which was attributed to mast bumping:
Accident Bell 206L-1 LongRanger II N114AE, Thursday 6 June 2013