Duplicate name servers are found when azurem_dns_zon is made the default option

Hello, if i deploy it as the default option for azure_dns_zone, i can see duplicate name servers in azure. Is this intended?

As far as I know, NS should not overlap.

Affected Resource(s)

azurerm_dns_zone

Terraform Configuration Files

resource "azurerm_dns_zone" "dns_zone" {   
  for_each            = toset(local.dns_zone_names)   
  name                = each.key   
  resource_group_name = azurerm_resource_group.rg.name    
  }

Debug Output

Panic Output

Expected Behaviour

Non-overlapping name server

Actual Behaviour

When i check the domain deployed by default, it is duplicated in the name server.

I don’t know if it was intended or not.

ex)
domain1.net    @ NS 172800 ns1-07.azure-dns.com. ns2-07.azure-dns.net. ns3-07.azure-dns.org. ns4-07.azure-dns.info.
domain2.com  @ NS 172800 ns1-07.azure-dns.com. ns2-07.azure-dns.net. ns3-07.azure-dns.org. ns4-07.azure-dns.info.
domain1.tv       @ NS 172800 ns1-07.azure-dns.com. ns2-07.azure-dns.net. ns3-07.azure-dns.org. ns4-07.azure-dns.info.

Steps to Reproduce

  1. default azurerm_dns_zone
  2. A large number of test domains(I have 70 domains.)
  3. terraform apply

Important Factoids

local : useast2 virginia

References

https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/resources/dns_zone