Origin is always present on proxy for ionic serve

Ionic Framework ionic-v3
9

Okay, we are doing this post in the WebApp:

this.post('/cloud/login', JSON.stringify(body), headers)

This is the configuration of your ionic.config.json

{
  "name": "web-client-ionic",
  "app_id": "",
  "type": "ionic-angular",
  "proxies": [{
      "path": "/api",
      "proxyUrl": "http://192.168.8.1/api"
  },{
      "path": "/cloud",
      "proxyUrl": "https://smart.blablablabla.com"
  }]
}

there is configured a proxy for cloud and this is the error in the browser:

POST http://localhost:8100/cloud/login 403 (Forbidden) polyfills.js:3

In the browser there is now CORS exception because there is not present the Access-Control-Allow-Origin header, and thats okay, this is working well by the proxy. But logging server and also consulting the server mantainer they have a CORS problem because the origin is present in the request, which should not be. Isn’t this the right way to handle this?