Monday : While Sunday's QF7 (B789 VH-ZNA) was early arriving in Dallas, the return QF8 pushed back 90 minutes late.
Then, while showing on the flight trackers as being in the air with a diversion to Brisbane for an 06:23 AEDT arrival time Tuesday morning, Qantas Flight Status shows the flight as "Cancelled" !
The onward flight to Sydney is shown on FlightRadar24 as departing at 7:40 AEDT, which would indicate an approximate arrival in Sydney of 10:00 AEDT.
Edit : there appears to be a flow on from this delay, with Tuesday Morning's QF11 SYD-LAX showing as delayed by 80 minutes for a new Sydney departure of 11:35 AEDT, with the same delay for its LAX arrival, now 07:20 PDT Tuesday
Tuesday : Ooops, sorry, forgot no DST in Qld, and also muddled BNE depart & SYD arrival. Thus B789 VH-ZNA arrived in Sydney with QF8 at the somewhat earlier time of 07:23 AEDT, just 60 minutes late. Qantas Flight Status is still showing the flight as "Cancelled".
Meanwhile B789 VH-ZNJ positioned from Melbourne to Sydney in the early hours as QF6002 to take over QF11 SYD-LAX which departed Sydney at 11:51 AEDT 96 minutes late, with LAX arrival estimated to be 06:50 PDT i.e. 50 minutes late.
B789 VH-ZND departed Jo'burg with QF64 at 19:09 SAT Monday, 89 minutes late, with expected arrival in Sydney of 15:37 AEDT, 72 minutes late.
Edit: this delay has flowed onto QF7 SYD-LAX which is now showing a 35 minute delay, for a revised 17:15 AEDT departure from Sydney, and a small (10 minute) delay on arrival at LAX at 16:10 PDT Tuesday.
B789 VH-ZNA has positioned to Melbourne also as QF6002 departing Sydney just before QF11 at 11:46 AEDT, arriving at 13:00 AEDT, while B789 VH-ZNH operating QF10 LHR-PER-MEL is shown as arriving on time at 19:40 AEDT.
However, Qantas Flight Status is currently showing today's QF9 MEL-PER-LHR (scheduled to depart at 16:15 AEDT) as departing Melbourne at 21:50 AEDT, 5 hrs 35 min late. This flight is currently also shown as arriving at LHR 5 hrs 20 min late at 10:20 GMT.
The remaining Melbourne B789 departure this evening, QF93 is currently shown as on-time at 22:10 AEDT. Which of the above B789s takes which flight is yet to be seen.