PATCH /api/v2/conversations/voice not updating queue target

Docs state: “To transfer a call, use the transfer endpoint on the conversation participants.” I’m sending a valid access token and the correct conversation ID. The request returns HTTP 200 OK, but the call stays in the original queue.

POST /api/v2/conversations/{conversationId}/participants/{participantId}/transfer
{
 "address": "new-queue-id",
 "type": "queue"
}

Why isn’t the transfer executing? The JSON structure matches the spec.