Speech Analytics API returning empty transcript array for voice interactions

Calling GET /api/v2/analytics/speech/textanalytics/transcripts/{conversationId} returns a 200 OK, but the transcripts array is completely empty even though the call lasted 5 minutes.

  • Cluster: us-east-1
  • API version: v2
  • Tried waiting 15 minutes post-call for async processing
  • Verified conversationId matches the voice interaction in the UI

The JSON payload looks like this:

{
 "transcripts": []
}

Why would the endpoint succeed but return no data?