Time will tell, but there are uncanny similarities of this accident to the following, notably power reduction in the left engine and loss of RPM, but not an engine failure per se.
https://dms.ntsb.gov/pubdms/search/h...6E4D369AA7935E
https://assets.publishing.service.go...pdf_022814.pdf
Read, and draw your own conclusions.
As with these two reports, I don't see the ATSB coming up with any definitive answer, other than an assumption of possible Power lever migration, which
Car RAMROD mentioned back at post #106. As I said, time will tell.