GGA incorrect delta output

[tkurki]

$GPGGA,200255.00,5310.81257,N,00525.70577,E,2,09,1.12,3.5,M,45.7,M,,0000*5A
generates

{
  "context": "vessels.4F443093",
  "updates": [
    {
      "source": {},
      "timestamp": "2017-09-10T18:41:29.063Z",
      "values": [
        {
          "path": "navigation.gnss",
          "value": {
            "source": {
              "type": "NMEA0183",
              "sentence": "GGA",
              "label": "signalk-parser-nmea0183",
              "talker": "GP"
            },
            "timestamp": "2017-09-10T20:02:00.000Z",
            "quality": 2,
            "satellites": 9,
            "antennaAltitude": 3,
            "horizontalDilution": 1,
            "geoidalSeparation": 45,
            "differentialAge": 0,
            "differentialReference": 0
          }
        }
      ]
    }
  ]
}

where real source is empty and the source data is under value.

[tkurki]

Furthermore there is no test for GGA that would check delta/full validity, which would have caught this.