wrapUpCode null in analytics detail queries

Pulling detail data via the JS SDK getAnalyticsDetailsInteractions endpoint. The response body returns wrapUpCode as null for every record, even though the agents definitely selected codes. Here’s the payload:

{
 "interval": "2023-10-01T00:00:00Z/2023-10-02T00:00:00Z",
 "groupBy": "wrapUpCode",
 "select": ["wrapUpCode", "durationSystem"]
}

Is this a known limitation of the detail API or am I missing a query parameter?