PATCH /api/v2/conversations/voice/{id} queue transfer returning 400 Bad Request

Getting a 400 when trying to transfer a voice conversation to a queue via the Conversations API. The docs say to needs a queueId, but the response just says invalid_request. Here’s the JSON body:

{
 "to": { "queueId": "abc-123-def" }
}
  • Endpoint: PATCH /api/v2/conversations/voice/{conversationId}
  • Status: 400
  • Error: invalid_request
  • Using Java SDK v6.0

Is the queue ID format wrong or is there a missing field?