Error in the system of changing legendary cards

On February 18 at 8:16 am, the option to change my “Reno Jackson” card for another legendary one appeared, since I have the diamond version.

I said yes and automatically I got “Brann bronze beard” card that I have repeated x2… I need you to please give me the option to change it for another legendary card.

server:NA

Thank you for your attention and have a good day.