PATCH /api/v2/conversations/voice/{id} to transfer to queue returns 422

Trying to transfer an active voice conversation to a different queue programmatically. The docs say to use PATCH on /api/v2/conversations/voice/{conversationId} with a transfer action.

Here is the payload I’m sending:

{
 "action": "transfer",
 "to": {
 "id": "queue-id-12345",
 "type": "queue"
 }
}

The request returns a 422 Unprocessable Entity. The error body says The transfer target is not valid. I’ve verified the queue ID is correct and the OAuth token has voice_call:write scope.

Tried adding wrapup codes to the payload, no change. Also tried setting type to user with an agent ID, which works fine, so the endpoint is reachable. Just stuck on queue transfers. Is there a specific format for the to object when targeting a queue? Or is this a known issue with the current API version?