No notification sound for new messages when there already are unread messages

Steps to reproduce

1. On phone A send message to phone B.
2. Notification appears on phone B. Notification sound is played.
3. Don't read the message on phone B.
4. Send another message from phone A to phone B.
5. The message text is appended to an old notification. No notification sound is played.

Expected behaviour

Notification sound should play every time a new message is recieved. This is the way it works on other messaging apps, so this is the expected behaviour. For preventing sound flood a 10 second delay could be set before allowing new notification sounds.

Actual behaviour

No notification sound is played, so if the person has missed the first notification, it is impossible to get their attention by sending another message.

Device brand and model

Any

Android version

11

Nextcloud Talk app version

17.1.0

Nextcloud server version

27.1.0

Talk version

17.1.1

Custom Signaling server configured

None

Custom TURN server configured

None

Custom STUN server configured

None

Android logs

No response

Server log

No response

Additional information

No response

Start by reproducing the notification flow on Android 11 with unread messages, using the listed Talk app and server versions. Trace the notification handling entry point and determine why appended notifications do not play a sound; done means each new message produces a sound while respecting any agreed delay, with regression coverage where the existing notification behavior is tested.