Below screenshot from FR24 playback just as they leveled off at 8000 - the liveatc audio seems to suggest the prop separated around here somewhere (controller asks would they like to maintain 8000 or continue descent).
Also... this AD would seem to be relevant?
https://www.gpo.gov/fdsys/granule/FR...nt-detail.html and
http://services.casa.gov.au/airworth...t7/CT7-006.pdf