The first cancellations of Qantas 787-9 flights in 51 days occurred yesterday - starting with VH-ZNC returning to Perth terminal without taking off for the Perth - London (LHR) sector of QF9.
https://www.flightradar24.com/data/flights/qf9#22a9f531
The QF10 London (LHR) - Perth sector departing 30 Oct was also cancelled (see Qantas Flight Status and FlightRadar24).
Today's QF10 Perth - Melbourne sector is being operated by VH-ZNC after it's over-night stop in Perth. This flight was delayed until after the arrival of the Emirates A380 (Qantas codeshare) flight EK420/QF8420 - linking from EK002/QF8002 - presumably with some priority passengers transferring from the cancelled QF10 flight.