Odd dimension ID in /api/metric-aggregates/ response

Hey Klaviyo team,

I’ve requested statistics for metric "Ordered Product" grouped by $attributed_message:

POST /api/metric-aggregates/ HTTP/1.1
Host: a.klaviyo.com
Authorization: Klaviyo-API-Key {{api_key}}
revision: 2023-10-15
Accept: application/json
Content-Type: application/json
Content-Length: 418

{
  "data": {
    "type": "metric-aggregate",
    "attributes": {
      "metric_id": "V5NtMc",
      "interval": "month",
      "measurements": [
        "count"
      ],
      "filter": [
        "greater-or-equal(datetime,2023-10-01T00:00:00)",
        "less-than(datetime,2023-11-01T00:00:00)"
      ],
      "by": [
        "$attributed_message"
      ],
      "page_size": 500,
      "timezone": "UTC"
    }
  }
}

In the response I see “long” and “short” IDs in "dimensions", for example:

                {
                    "dimensions": [
                        "01HDGWHBJRWC0VZZDTS611Q4WJ"
                    ],
                    "measurements": {
                        "count": [
                            1.0
                        ]
                    }
                },
                {
                    "dimensions": [
                        "QRmivv"
                    ],
                    "measurements": {
                        "count": [
                            99.0
                        ]
                    }
                },

Using “long” ID, I’ve managed to retrieve properties of the campaign on which the event was attributed:

        "type": "campaign",
        "id": "01HDGWHBJRWC0VZZDTS611Q4WJ",
        "attributes": {
            "name": "EMEA_DE_DL_BARBIE_Email_2023_251023_RET_MAT_World-of-Reveal_PK39_BAU",
            "status": "Sent",
            "archived": false,
...

But using “short” ID, I’ve got error 404 “Not Found”:

{
    "errors": [
        {
            "id": "87e541fb-86a8-4952-9d68-f570e4d0c29b",
            "status": 404,
            "code": "not_found",
            "title": "Not found.",
            "detail": "A campaign with id 'QRmivv' does not exist.",
            "source": {
                "pointer": "/data/"
            }
        }
    ]
}

I’ve also checked - it’s not a flow or list.

Could you please clarify which ID I got here?

Thanks &regards,

Evgeniy