If you add NS records to a DNS zone on Enhance that is connected to Cloudflare, the NS records are not pushed to the Cloudflare zone. No error is shown and the NS records still show in Enhance.
Quite a hard one to diagnose as you can imagine.. I will report this to Enhance as well.. but be careful with this one.
Why would you be adding NS records? At times, providers like Klaviyo (not only) use NS records to have an entire subdomain delegated to their DNS so they can manage things like DKIM records etc. This isn't the only use case.
Support confirmed that no NS records are synced to Cloudflare. I guess this comes from not wanting to sync apex NS records and break things.. but subdomain NS records should be synced.. in my opinion, at least a warning should be shown if certain records are not synced.. and this should be documented somewhere.