The YITH Gift Card plugin prices are not copied to the translated products.
Solution:
1- Go to WPML-> Settings-> Custom fields section
2- Click on "Show System Fields"
3- Search for the "_gift_card_amounts" field
4- Set it to "Copy"
5- Click "Save"
6- Edit the product in the default language, and update it
7- Update the translation
8- Clear the cache and check the front end
