Tree views with json drilldown produces wrong tmeasurement fields

[Piiit]

https://mobility.api.opendatahub.testingmachine.eu/v2/tree/EChargingPlug/echarging-plug-status/latest?select=pmetadata.state,sname

... produces wrong result:

    "offset": 0,
    "data": {
        "EChargingPlug": {
            "stations": {
                "00-30-D6-09-5F-8A-0": {
                    "sdatatypes": {
                        "echarging-plug-status": {
                            "tmeasurements": [
                                {}
                            ]
                        }
                    },
                    "sname": "Tamm-200770-13103",
                    "sparent": {
                        "pmetadata": {
                            "state": "TEMPORARYUNAVAILABLE"
                        }
                    }
                }
            }
        }
    }

tmeasurements should not be there, the empty object should be removed and therefore the list would be empty and also removed from results