400 Bad Request on Web Messaging deployment update - JSON payload issue

Is it possible to customize the launcher position via the API?

“To modify the deployment, send a PUT request to /api/v2/webmessaging/deployments/{deploymentId} with a JSON body containing the ‘settings’ object.”

I am trying to update the color and position using this payload:

{
 "settings": {
 "launcherPosition": "bottom-right",
 "primaryColor": "#FF0000"
 }
}

I get a 400 Bad Request. The response says “Invalid property path”. I am using the Platform SDK Python client. Is the JSON structure wrong for this endpoint?