MEL_Traveller, it looks like B788 VH-VKD must have failed in MEL on the evening of Monday 8 January as JQ35, normally the 1855 hours MEL - DPS did not depart until 0802 on Tuesday 9, landing in Bali at 1025. JQ36 was similarly delayed with that flight becoming airborne at 1151 for a 1951 hours at gate arrival in MEL last night. The B788 then formed JQ17 from MEL to as you suggest HKT, taking off at 2201 rather than its pushback time of 1530 mid afternoon, and arriving HKT at 0238 hours, 378 minutes late.
VH-VKD then naturally formed JQ18, the scheduled 2145 hours HKT back down to MEL that this morning (10 January 2018) took off at the unattractive time of 0405 hours, meaning suggested arrival in MEL at 1630 this afternoon, 370 minutes late.