Hi @tom.goeckeritz
I think I may be missing what is happening for you as it is doing what I would expect when I try:
[
  {
    "start": "2024-11-01 00:00:00",
    "start_date": "2024-11-01",
    "start_time": null,
    "start_utc": "2024-11-01 00:00:00",
    "start_date_utc": "2024-11-01",
    "start_time_utc": null,
    "end": "2024-11-01 00:00:00",
    "end_date": "2024-11-01",
    "end_time": null,
    "end_utc": "2024-11-01 00:00:00",
    "end_date_utc": "2024-11-01",
    "end_time_utc": null
  },
  {
    "start": "2024-11-01 21:00:00",
    "start_date": "2024-11-01",
    "start_time": "21:00:00",
    "start_utc": "2024-11-01 21:00:00",
    "start_date_utc": "2024-11-01",
    "start_time_utc": "21:00:00",
    "end": "2024-11-01 22:00:00",
    "end_date": "2024-11-01",
    "end_time": "22:00:00",
    "end_utc": "2024-11-01 22:00:00",
    "end_date_utc": "2024-11-01",
    "end_time_utc": "22:00:00"
  }
]
The top record doesn’t have times set, and the second record does. If I have a record with no date, then that field won’t be in the response at all.
not sure if that helps or not, let me know and we can delve deeper if need be 
[
  {
    "field_id": 503422,
    "external_id": "date",
    "label": "Date",
    "type": "date",
    "field_type": "range_date",
    "config": {
      "label": "Date",
      "slug": "date",
      "external_id": "date",
      "show_description": false,
      "required": false,
      "always_hidden": false,
      "hidden_if_empty": false,
      "settings": {
        "calendar": false,
        "time": "enabled",
        "end": "enabled",
        "is_due_date_of_status_field": false
      }
    },
    "values": [
      {
        "start": "2024-11-01 00:00:00",
        "start_date": "2024-11-01",
        "start_time": null,
        "start_utc": "2024-11-01 00:00:00",
        "start_date_utc": "2024-11-01",
        "start_time_utc": null,
        "end": "2024-11-01 00:00:00",
        "end_date": "2024-11-01",
        "end_time": null,
        "end_utc": "2024-11-01 00:00:00",
        "end_date_utc": "2024-11-01",
        "end_time_utc": null
      }
    ]
  },
  {
    "field_id": 503422,
    "external_id": "date",
    "label": "Date",
    "type": "date",
    "field_type": "range_date",
    "config": {
      "label": "Date",
      "slug": "date",
      "external_id": "date",
      "show_description": false,
      "required": false,
      "always_hidden": false,
      "hidden_if_empty": false,
      "settings": {
        "calendar": false,
        "time": "enabled",
        "end": "enabled",
        "is_due_date_of_status_field": false
      }
    },
    "values": [
      {
        "start": "2024-11-01 21:00:00",
        "start_date": "2024-11-01",
        "start_time": "21:00:00",
        "start_utc": "2024-11-01 21:00:00",
        "start_date_utc": "2024-11-01",
        "start_time_utc": "21:00:00",
        "end": "2024-11-01 22:00:00",
        "end_date": "2024-11-01",
        "end_time": "22:00:00",
        "end_utc": "2024-11-01 22:00:00",
        "end_date_utc": "2024-11-01",
        "end_time_utc": "22:00:00"
      }
    ]
  }
]