Coupon issue while using Protected Content

Hi,

We seem to have a problem with applying coupons at the moment. I create a coupon that is 100% of a particular membership. When a user tries to apply the coupon it correctly says that the subscription will now be free. However, when you click the Signup button to confirm it takes you to the "Register" page and asks to complete payment. If you click "Complete Payment" it brings you back to the overview of the membership, but with the full price again. The user is not added to the membership.

Best Regards,
Simon