hostgroups update

[a-dawg]

hi,
when apply x2, on the second apply of the manifest below I am getting

  # hitachi_vsp_hostgroup.hg["xxxx"] will be updated in-place
  ~ resource "hitachi_vsp_hostgroup" "hg" {
      - hostgroup_number  = 4 -> null
        id                = "CL2-A4"
        # (5 unchanged attributes hidden)

        # (2 unchanged blocks hidden)
    }

here is the manifest

resource "hitachi_vsp_volume" "volume" {
  name    = "voltest"
  pool_id = 1
  serial  = var.serial
  size_gb = 10
}

resource "hitachi_vsp_hostgroup" "hg" {
  serial         = var.serial
  hostgroup_name = "hostgrouptest"
  port_id        = "CL2-A"
  # wwn            {
  #   host_wwn = each.value.wwns
  # }
  host_mode_options = [54, 63, 114]
  host_mode         = "VMware Extension"
  # SET of LUN

  lun {
      ldev_id = hitachi_vsp_volume.volume.volume.0.ldev_id
  }
  depends_on = [ hitachi_vsp_volume.volume ]
}

on the second apply it should not update the the hostgroup but it does and I am getting this error_

hitachi_vsp_hostgroup.hg: Modifying... [id=CL2-A4]
╷
│ Error: An error occurred in the storage system. (message = The same host group name is already installed in the port.)
│ 
│   with hitachi_vsp_hostgroup.hg,
│   on main.tf line 44, in resource "hitachi_vsp_hostgroup" "hg":
│   44: resource "hitachi_vsp_hostgroup" "hg" {
│