No incoming message notifications for second, third, and further messages. Only the first message triggers a sound notification.

When a new message is received, only the first message triggers the message sound, second and further messages do not trigger a new incoming message sound. Pls. fix this, so that every message is signalled to the user.

Happens on these devices:

• HUAWEI P8 LITE (Android 6.0)
• HUAWEI P8 LITE 2017 (Android 7.0)