It’s just a ploy to stop new joiners obtaining a licence and leaving straight away. There’s nothing CX can do legally in HKG to obtain this amount apart from hold back wages/PFUND perhaps.
Same situation with their old “forgivable loan” they used to pay and try and claim back if a pilot left before 5 or 6 years.
most airlines now have a bond, EK is about 45,000USD over a few years too