Found a hint by HKFA, that the "anonymous" Gao Shan (2) https://hkmdb.com/db/people/view.mhtml? ... ay_set=eng
is another alias of actor Lo Duen (wo has many "real" alias BTW) https://hkmdb.com/db/people/view.mhtml? ... y_set=big5

HKFA found 5 "collabations", 4 of them has Gao Shan (2) as actor, while Lo Duen is Production Manager each time