It was an Air China crew (PRC, not Taiwan). The PRC uses PANSOPS, Taiwan and some airfields in Korea use TERPS. The Air China crew weren't aware of the difference between TERPS and PANSOPS circling areas. Incheon and Gimpo now use PANSOPS, but Pusan has remained using the TERPS standards for it's procedures as the circling approach won't work if using PANSOPS. The hill on fianls gets in the way, as the Air China crew found out!