Using an icon in notification api not working

Just checking if /api/notify should accept an icon on the ATV app? I see the notification, but setting icon to either fa-house or sf-house doesn't work.

The icon option is not mentioned in Channels Support - Channels API

But it is on the page served from the app: http://:57000/api/

I am using android (beta 8.5.2116 ) on nvidia shield / icon does not seem to work either