Web Messaging Guest API: Typing indicators not triggering on POST /interactions/messaging

We’re building a custom chat widget and need to push typing indicators and read receipts directly via the Guest API. The documentation for the DFO channel is thin on this specific endpoint. I’m hitting POST /api/v2/interactions/messaging/{interactionId} with a JSON payload containing the event type, but the agent side doesn’t show the typing bubble. Here’s the request structure we’re using:

{
 "eventType": "typing",
 "direction": "TO_AGENT",
 "timestamp": "2023-10-27T14:30:00Z"
}

The response is a 204 No Content, which suggests the server accepted it, but nothing happens in the UI. I’ve verified the interactionId is valid by checking the conversation log in the admin portal. The message events work fine, but these auxiliary events seem to drop silently. Is there a specific header or content-type requirement I’m missing? We’re using the standard Bearer token flow.

I’ve also tried sending a read event with the same structure, replacing eventType with read and adding the messageId field. Still no luck. The WebSocket connection is stable, and we’re receiving incoming messages correctly. It feels like the API endpoint for these events might be different or require a different scope. The standard messaging:conversation:write scope is active on the service account. We’re in the us-east-1 region. Any pointers on the correct payload format or endpoint for these non-message events would be appreciated. We’re stuck on this for two days now. The client is pushing hard for this feature. Need to know if it’s even supported via REST or if we have to stick to the widget’s internal methods.