Yep , my son who was on the flight sent a one word email ..weather !!
But from what I could find from flight aware the wx at scheduled arrival time was vfr, but dunno how to find past metar, speci or tafs for vhhh.
On a similar question, I seem to remember QF never used to carry alternate fuel but 60 mins fixed reserve plus any tempo or inter fuel reserves as the case may be.
Is that still the case ?
the 3 longhaul carriers I worked for all carried alternate fuel plus any wx holding fuel as well.