Flow Actions - is not a nested object on the

In Klaviyo API Documentation Reference it gives an option to select nested objects for render_options and send_options (image below)

It also suggests to make a API call that theoretically should succeed:

curl --request GET \
     --url 'https://a.klaviyo.com/api/flows/id/flow-actions/?fields[flow-action]=render_options.shorten_links,send_options.use_smart_sending&page[size]=50' \
     --header 'Authorization: Klaviyo-API-Key your-private-api-key' \
     --header 'accept: application/json' \
     --header 'revision: 2023-06-15'

I just copied it from API Documentation.

But when I perform such request I get:

{
    "errors": [
        {
            "id": "XXX",
            "status": 400,
            "code": "invalid",
            "title": "Invalid input.",
            "detail": "'render_options.shorten_links' is not a nested object on the 'flow-action' resource",
            "source": {
                "parameter": "fields"
            },
            "meta": {}
        }
    ]
}

The same situation with EVERY nested field for render_options and send_options.

As soon as I remove those nested params API call succeeds.

Request for nested objects in other API resources, for example Campaign message succeeds (https://a.klaviyo.com/api/campaign-messages/XXX/?fields[campaign-message]=content.subject)