Ticket API - get and edit Follow-up details

Hi,
I'm trying to get (and update) the Follow-up details in a ticket.
I have the following follow-up questions in my tickets:
but when I do a GET call to https://{{host}}/API/v3/tickets/T-154,
the reply I get is:
{

    "result": {

        "key": "T-154",

        "name": "Untitled tickettest for ticket",

        "ownerId": "UR_0jIHlLHxDGWMCJT",

        "status": 2,

        "priority": 0,

        "responseId": "R_3fcwsi8X8dCXDvZ",

        "sourceId": "SV_ene1IeRozHdbOXb",

        "rootCause": null,

        "parent": null,

        "createdAt": "2020-11-10T15:46:49.000Z",

        "updatedAt": "2022-04-11T10:16:20.111Z",

        "closedAt": "2022-04-11T10:16:20.111Z",

        "ticketData": {

            "elements": [

                {

                    "key": "given NPS score",

                    "value": "7"

                }

            ]

        },

        "eventsLink": "https://iad1.qualtrics.com/API/v3/tickets/T-154/events"

    },

    "meta": {

        "requestId": "64ba55e8-78d4-4cc6-bb78-a0fd6daae745",

        "httpStatus": "200 - OK"

    }

}

The documentation mentions on https://api.qualtrics.com/api-reference/b3A6NjExMjI-retrieve-ticket that there should also be:
"followUpDetailsSurveyId": "string",
"followUpDetailsResponseId": "string"
which I think would contain what I'm looking for,
but I'm not getting those in my calls...
anyone who has some advice?

Kr,
Joyca