Can I ask if you booked this with QF points?
I am having a similar issue with returning from Rome to Mel. I can book QF award flight FCO to HKG (via TPE) and can then book HKG to MEL (again via (TPE). Alternatively, I can book FCO to TPE but I can't book TPE to MEL. The QF site Multi-city tool won't even allow TPE as an option to start a Classic Awards flight.
