Resolved
We're happy the DNS cluster is still returning valid records, so this issue is now being closed. Thanks for your patience.
Monitoring
We have now restarted the Cache node on the secondary cluster. DNS records are now being returned as expected. We're still monitoring this though.
Please note: Due to DNS caching on resolvers these can take 4 hours to propagate.
Investigating
We're seeing issues on Zones which has been migrated on the last couple of moved. We're seeing template Zone records being returned on the secondary nodes which is resulting in bad results for Custom records such as MX or subdomains.
We're currently investigating this as a priority and will update as this is progressed.
