Registrant Contact change failed successfully

I requested a change in Registrant Contact for my domain and successfully received an email. I open the link, press accept, and it says COR decision applied. I go back to my dashboard but nothing has changed. Registrant Contact Change Pending still shows. When I press resend email, no email is sent. Refreshing the page for change gives me This change of registrant request is not valid.. This is not a temporary issue. I tried the same thing last month and gave up.

Note that I’m able to successfully change the details for everything except Registrant Contact. Administrator Contact etc has been changed just fine