There are differences to how stop limit orders are executed between the US and Hong Kong markets due to the different market sessions.

US Markets

US Markets have Pre-Market and After-Market sessions that stop limit orders can be executed (if the price condition is met).

This means if you place stop limit orders before or after the Main session they will be transmitted for execution at the Pre-Market or After-Market prices (if the price condition is met).

Hong Kong Market

Stop limit orders placed prior to market open or after closing will be queued for execution at the next open Market session.

Check out the overview of market statuses and order types for more information.