A Start of Authority (SOA) DNS record stores administrative information about the zone. There is no need to configure SOA records when you are using Cloudflare authoritative nameservers. We automatically create the SOA record when you move your zone to Cloudflare.
When Cloudflare nameservers are the authoritative name servers of the zone, some of the fields in the SOA record are set differently from other common DNS servers.
SOA Serial Number
It is common to set the serial number with a date format for most DNS servers. However, Cloudflare uses a different methodology to generate those serial numbers. It is normal that the Cloudflare SOA serial does not follow the recommended date format.
You can ignore warnings from third-party tools regarding Cloudflare SOA serial numbers not being valid.
SOA Expire Value
The Expire Value tells how long a secondary name server should continue giving out authoritative replies after it has no longer heard from the master server. RFC recommends 1209600 to 2419200 seconds (2-4 weeks). However, Cloudflare nameservers may use a shorter value.
You can ignore warnings from third-party tools regarding Cloudflare SOA Expire Values being out of the recommended range.