Branch deploy ssl / custom subdomain

wrt: https://stellar-lily-7c3892.netlify.app/

I am trying to get a branch deploy to work.
I had a custom domain set up to be [abc].dedfam.world AND picked the same branch name [abc] to be my subdomain. It seems that the code deployed to the subdomain branch gets overwritten by the main branch if I have a custom domain setup, which is not what I want. However, if I remove the custom domain, I lose the SSL certificate. How do I keep the SSL without having the branch deploy overwritten by the main branch? Should setting up a custom domain even have the effect of overwriting the branch deploy with the main branch at the same url?

I am not having an build errors in the console when deploying so have not attached.

Hi, @heyfam. We have a support guide about branch subdomain SSL without Netlify DNS here:

Would you please read that support guide and then let us know if there are any questions?

If there are no questions, please let us know when the required DNS records have been created and we’ll update the SSL certificate to include them.