Entra External ID sign in page generated under custom domain name in looks different

Hi!

I have tried following the guide on using a custom URL domain for Entra External ID with Azure Front Door.

https://learn.microsoft.com/en-us/entra/external-id/customers/how-to-custom-url-domain

But when I use the ciamlogin.com domain, the login page looks different than when I use the custom domain. The https://woodgrovedemo.com/ reproduces the issue, so I've posted some screenshots from that. Why is there now a "Sign-in options" expander and a "Can't access your account" link on the custom domain? Somehow, the sign-in is not in the correct state, I presume. Does anyone have an idea why this is?

If possible, I want to be able to use the look from the ciamlogin.com domain on the custom domain. Otherwise, I can not use the custom domain solution, unfortunately.

Best regards,

Johan