Cathay Pacific flight/s CX171/170 delay of 6hours today ops by A359 B-LRM

Cathay Pacific Airways flight CX171 from Hong Kong to Perth overnight was delayed just over 6hours for reasons unclear, the flight operated by A350-941 B-LRM c/n 075 departed ex: Chek Lap Kok Intl Airport (VHHH) Hong Kong at 21.11hrs & arrived into Perth Airport (YPPH) at 04.06hrs & departed at 05.55hrs as flight CX170 returning back to Hong Kong. Hexcode: 780AB8