According to the report in the Sydney Morning Herald (from newswire AAP...) which got it from the ATSB
https://www.atsb.gov.au/publications...r/ao-2017-044/ the aircraft was in the Hold at 22,000 feet and on
autopilot at the time.
My question is "How is it that the autopilot could get the aircraft into this condition?" Does this suggest it may have been in the wrong mode?