I just asked my TA (who did me a mixed class PE HKG-SYD, Economy SYD-HKG) booking if I could do Business/Economy HKG-BKK-HKG and was told the fare classes couldn't mix.
Is this route specific or is the TA wrong? I will call CX when I have time tonight but I just wondering why I was told this when they didn't have problems doing mixed class the other day (albeit on QF)