I had to create 12 NS records and 3 CNAME records in order to verify certificates for our cloud.
Unfortunately I created the NS records first… and encountered the error as per title of this post.
So I ended up adopting this workaround Cannot create a non-glue record that is beneath a delegated child zone. (Code: 89018) - #9 by ilg
which meant I had to delete all 12 NS records, then create the 3 CNAMEs then re-create the 12 NS records again…
This is clearly a bug as it forces the user to delete and re-create the same record. The bug has been known to you through the post I linked above, and other posts such as this one 89018 Cannot create a non-glue record that is beneath a delegated child zone
Do you people at Cloudflare have an ETA for resolving this issue? We often get new certificates so we often have to go through this procedure and would like to see this resolved.