No double miles for HKG-ICN-HKG on 31 Aug, return 3 Sep. But double miles for all subsequent sectors booked:- HKG-YVR-HKG (departing 8 Sep), HKG-SIN-HKG in Sep, HKG-YVR-LAX-HKG in Nov.
The Asian sectors are all booked in economy as well, so doesn't seem to be restricted to business class.
Strange.