Error 1000: DNS points to prohibited IP (Non-Proxied CNAME)

I’m getting “Error 1000: DNS points to prohibited IP” when navigating to a new DNS entry (CNAME without proxying).

The destination is a third-party service that is also using Cloudflare. We already have another CNAME set up in the same domain to the same vendor using the same settings (the only difference is the host and the destination host).

To be clear,
If our domain is EXAMPLE.COM and the vendor’s domain is VENDOR.COM
Then the vendor has created a site for us called EXAMPLE.VENDOR.COM and I’m trying to get VENDOR.EXAMPLE.COM to point to the service they created for us.

I don’t understand why a non-proxied CNAME would care about proxy loops and I think something is miswired somewhere.

I deleted the whole entry and recreated it and now it works fine. Something was bugged.