Unforecast fog, alternate available but continues to destination and autolands in SY. On that day QF2, 744 using the same fuel policy, diverts to CB.
IIRC, when the TTF first issued it was still above ALT crtieria thus the A330 committed. The 744 was a bit behind (and slightly more gas) and subsequent TTF arrived in time for them to divert to CB. I think the A330 was on finals without CB fuel when the TTF below alternate criteria was issued.