adding dns zone should add DKIM records
When adding a DNS zone, if a corresponding mail zone exists with a DKIM record set, that DKIM record should be added to DNS records. (Applies both to the dns wizard and adding a zone manually.)
Background: Having found that many of our DNS zones to not have DKIM records even though they are configured in the Email domain, the likely reason is the order of adding them - if you add an Email domain first, including a DKIM records, and add the DNS zone second, you will not have any DKIM record created in DNS. Mail will still be signed with the DKIM key, just not verifiable.