Please consider updating the Android application to enable onlyAlertOnce.
This will cause app notifications to alert only if there is not a previous notification in the notification shade. I get a lot of queued notifications which all alert in sequence, often with the sound overlapping the previous notification.
This is a native feature of Android and would bring the application up to the standards of other applications using Android notification features. It is also supported in Android versions as old as 5.1.