When you add an address list entry with a domain name as address, the router populates dynamic entries for the same list name with IP addresses obtained from the DNS lookup. The entries have time out taken from the TTL of the records. When the timeout elapses, it will make DNS lookups again and repopulate the dynamic address list entries. You can see this recent bug fix item in 7.21 as proof that the TTL is used:
That look up uses and also updates the DNS cache under IP -> DNS, which is the same cache used when the RouterOS ACME client needs too look up the domain in the directory URL. So the ACME client will see the same IP addresses as what currently listed in the address list if the TTL is not too long because it will most probably reuse the same cached DNS record from the recent address list update.
There is a chance of mismatch if the TTL is long enough and the DNS cache is full causing old records to be evicted.