The .co.za registry, also known as ZACR (https://www.registry.net.za/) does nameserver checking on .co.za domains when a nameserver update is done.
For some or other reason it does not allow the update to the Cloudflare servers and I saw this note
During these nameserver checks, the registry ensures that the new nameservers are in fact configured correctly for the domain name and are answering authoritatively for the domain name.
If any of the check should fail, to any nameserver specified in the nameserver update, ZACR will decline the nameserver update.
This gives the appearance that the nameservers for the domain are reverting back to their previous values.
Please could anyone who has experienced the same, help me ?