List All Subscriptions for a Subscription Group: "subscriptionAvailability" is not a valid relationship name

I try to fetch subscriptions with included relationships according to the documentation

GET https://api.appstoreconnect.apple.com/v1/subscriptionGroups/12345678/subscriptions?include=[ "appStoreReviewScreenshot", "group", "introductoryOffers", "offerCodes", "prices", "promotedPurchase", "promotionalOffers", "subscriptionAvailability" ]

The form of include field is taken from the official OpenAPI spec

In the response I get a bunch of errors What am I doing wrong?

{
  "errors": [
    {
      "id": "0c02ac40-47c6-4107-b725-930e938a587f",
      "status": "400",
      "code": "PARAMETER_ERROR.INVALID",
      "title": "A parameter has an invalid value",
      "detail": "'[ \"appStoreReviewScreenshot\"' is not a valid relationship name",
      "source": {
        "parameter": "include"
      }
    },
    {
      "id": "cf2e214a-cab7-4e63-8971-d8974b0903f6",
      "status": "400",
      "code": "PARAMETER_ERROR.INVALID",
      "title": "A parameter has an invalid value",
      "detail": "' \"group\"' is not a valid relationship name",
      "source": {
        "parameter": "include"
      }
    },
    {
      "id": "56d7e72f-cf29-4fac-9456-79074e294567",
      "status": "400",
      "code": "PARAMETER_ERROR.INVALID",
      "title": "A parameter has an invalid value",
      "detail": "' \"introductoryOffers\"' is not a valid relationship name",
      "source": {
        "parameter": "include"
      }
    },
    {
      "id": "abdaf783-9a95-4053-a614-bcee7aedab45",
      "status": "400",
      "code": "PARAMETER_ERROR.INVALID",
      "title": "A parameter has an invalid value",
      "detail": "' \"offerCodes\"' is not a valid relationship name",
      "source": {
        "parameter": "include"
      }
    },
    {
      "id": "53270b6c-f0f5-4d18-9004-2c99ce9905bd",
      "status": "400",
      "code": "PARAMETER_ERROR.INVALID",
      "title": "A parameter has an invalid value",
      "detail": "' \"prices\"' is not a valid relationship name",
      "source": {
        "parameter": "include"
      }
    },
    {
      "id": "9676075f-d2fb-493e-b093-c973e3b103d2",
      "status": "400",
      "code": "PARAMETER_ERROR.INVALID",
      "title": "A parameter has an invalid value",
      "detail": "' \"promotedPurchase\"' is not a valid relationship name",
      "source": {
        "parameter": "include"
      }
    },
    {
      "id": "451dd333-1c75-4e22-90e1-40c6532fa465",
      "status": "400",
      "code": "PARAMETER_ERROR.INVALID",
      "title": "A parameter has an invalid value",
      "detail": "' \"promotionalOffers\"' is not a valid relationship name",
      "source": {
        "parameter": "include"
      }
    },
    {
      "id": "b0afb70e-ab6a-4aa3-9840-3e94844d3385",
      "status": "400",
      "code": "PARAMETER_ERROR.INVALID",
      "title": "A parameter has an invalid value",
      "detail": "' \"subscriptionAvailability\" ]' is not a valid relationship name",
      "source": {
        "parameter": "include"
      }
    }
  ]
}