[johnsnow]

I noticed recently when I tried to purchase The Road by Cormac Mccarthy off of the Kobo website that the option to enter promo codes was available on the purchase screen. I knew from previously that this book did not accept promo codes so was kind of surprised to see it there. Anyway long story short you can enter all the valid codes you want and they will all come up as invalid. I tested the code on other books I know that do accept promo codes and they worked fine.
When I attempt the purchase under private browsing a different checkout screen comes up and there is no option for promo codes. Why do the checkout screens look completely different on the same website, and why would the promo code window be available when the book does not accept promos? This also happens on The GoldFinch by Donna Tartt.
Just curious has anyone else experienced this and what is the reason it would be happening?