domain name system - Wildcard 'A' record overriding CNAME record

I have a Wildcard * A record for self-registration of subdomains by users on our web app. All works fine.

I now need to set up an alias for support.mydomain.com to point to mydomain.freshdesk.com. I created a CNAME record as per instructions however it appears my Wildcard A record is overriding the CNAME entry.

Any thoughts on how to resolve this? I need the wildcard so creating an A record for each user subdomain is not possible.

Thanks.