Thank you for contacting us. I am happy to help you.
I have tested your site and it is working as expected.
Visit to hidden link and it redirect to hidden link since my browser has ENG language.
Here is also a screencast :
hidden link
Have also in your mind :
Are you using a new session?
Remember that WPML will only redirect once. You need to clear all cookies or start an incognito browser (which always has a fresh history). This starts a clean session and simulates a new visitor.