Updating participant attributes on active voice interaction via PATCH /api/v2/conversations/voice/{id}

Running into a weird issue with updating participant attributes on a live voice call.

We have a Python service handling the tracing context via OpenTelemetry. When a specific event fires, we need to drop a custom attribute (trace_id) onto the participant object so it shows up in the recording metadata later.

I’m hitting PATCH /api/v2/conversations/voice/{conversation_id} with this payload:

{
 "participants": [
 {
 "id": "participant-uuid-here",
 "attributes": {
 "trace_id": "0af7219e6e4d..."
 }
 }
 ]
}

The call returns a 200 OK. The response body confirms the attribute is set. But when I immediately GET the conversation details, the attributes field on that participant is empty.

If I wait about 10-15 seconds and GET again, the attribute appears. This lag is breaking our real-time correlation logic in the tracing backend. We need the attribute to be available immediately for downstream processors.

Is there a specific header or query param to force synchronous persistence? Or am I missing a step in the API contract for live interactions?