Critical Alert not disappearing

Question

I have implemented critical alerts in one of my app, which is working fine. But I have a few questions about some of its behaviour.

• Critical alerts banner not disappearing unless clicked.

• Normal Notification's sound also not playing, when the critical alert banner is over the app

Scenario

1. Launch the app on iOS.
2. Login as a User A Send a normal alert to User A  (Received alert with sound notifications).
3. Send a Critical Alert message to User A (Received message with sound notifications and don't read the urgent message).
4. Again send a normal message to User A (User A did not receive sound notifications until he read the critical alert).

Please clarify if these are the default behaviour of Critical Alerts.