Why is 100% Off Coupon still asking for Credit Card?

Hi, even though I put a 100% off coupon code in, the modal is still requiring a credit card. The code works find showing $0 due. So not sure if I am missing something. I noticed in an MS article (link below) that once you put in a forever code the credit card field disappears. https://help.memberstack.com/en/articles/3850094-coupons-discounts-and-promotions