cb: created empty subnet contains unset values

1. creating empty subnet:

{'arguments': {'remote': {'type': 'mysql'},
               'server-tags': ['abc'],
               'subnets': [{'interface': '$(SERVER_IFACE)',
                            'pools': [{'pool': '192.168.50.1-192.168.50.100'}],
                            'subnet': '192.168.50.0/24'}]},
 'command': 'remote-subnet4-set',
 'service': ['dhcp4']}
[
  {
    "arguments": {
      "subnets": [
        {
          "id": 1,
          "subnet": "192.168.50.0/24"
        }
      ]
    },
    "result": 0,
    "text": "IPv4 subnet successfully set."
  }
]

2. config reload
3. config get:

...
        "subnet4": [
          {
            "4o6-interface": "",
            "4o6-interface-id": "",
            "4o6-subnet": "",
            "authoritative": false,
            "boot-file-name": "",
            "calculate-tee-times": false,
            "id": 1,
            "interface": "enp0s10",
            "match-client-id": true,
            "next-server": "0.0.0.0",
            "option-data": [],
            "pools": [
              {
                "option-data": [],
                "pool": "192.168.50.1-192.168.50.100"
              }
            ],
            "rebind-timer": 2000,
            "relay": {
              "ip-addresses": []
            },
            "renew-timer": 1000,
            "reservation-mode": "all",
            "reservations": [],
            "server-hostname": "",
            "subnet": "192.168.50.0/24",
            "t1-percent": 0.5,
            "t2-percent": 0.875,
            "valid-lifetime": 4000
          }
        ],
        "t1-percent": 0.5,
        "t2-percent": 0.875,
        "valid-lifetime": 4000

...

As it can be seen probably default values are return. It also is visible that some global params have default values while they were NOT set as well.