Thanks.as I understand, when making changes to a booking they need to re-select all the previously booked flights back into the booking.....and the married leg becomes unavailable to rebook when adding the flights back in. A pain.
As an aside, finding award seats in/out of Australia is such a huge pain at the moment with CX largely unviable as an option, QR not releasing more than 1 ticket on each flight, Japan being a non-ideal transit point for the time being, AY's cutbacks to its Asia flying operations, QF's international network not fully back in operation, EK new carrier charges encouraging people who used to book them to book QF/JL/QR instead, etc etc. Really hope the situation improves over the coming months.