Genesys Speech Analytics API returning empty transcript array

Trying to pull the full voice-to-text transcript for a specific conversation via GET /api/v2/analytics/conversations/details/query. The request returns a 200 OK, but the transcript objects in the response are empty arrays.

Here is the query payload I’m sending:
{
“dateFrom”: “2023-10-01T00:00:00.000Z”,
“dateTo”: “2023-10-01T23:59:59.999Z”,
“groupings”: [{“type”: “conversation”}],
“filter”: {“type”: “and”, “clauses”: [{“type”: “field”, “field”: “conversationId”, “operator”: “equals”, “value”: “abc-123”}]}
}

The transcript array is just . Did I miss a parameter to enable transcription retrieval?