Gift Box is compatible with the multi-currency checkout when the specific method of adding free gifts to orders, called "Compatibility with all discount types," is selected. You can choose this method in the Settings section of the app.
Learn more about the gifting methods in the How are free gifts added to orders? article.
Please note that with the alternative method called "Compatibility with discount coupons only," Gift Box is unable to support the multi-currency checkout due to use of draft orders. However, we have integration with this feature on our roadmap.
If you're experiencing issues with free gifts not showing in your cart, our support team is available to assist you through the in-app chat or via email at support@digismoothie.com.