I wanted to give you an update on this case.
The "silent" notification that occurs is coming from our app, and it tells the user this is happening (so that they are aware of it). It is a designed feature. This feature can be helpful so that you do not miss any alerts/chats. -It will remain in the notification area until the status changes or the user swipes it away.
Changing the Vina notification settings to not show these notifications will also disable chat and other notifications, so that is not recommended.
If the Android users do not want this feature, and since it is designed this way, our course of action is for you to submit an Idea (Feature Request) for them to be able to disable it on our support portal.