The issue is when the android app is killed. If you receive push notification with high priority and your app don't catch this notification correctly, after some notification, your application is banned from android for minutes.
In our case with android, we sent push on call_ended and call_updated but because the app is killed we don't use it and we are banned by android
These pushes was added for IOS at first, but we choose to send it to all device without any test of os.
Another approach should be used