Sound notifications not working Mattermost desktop app macOS 2025

After skimming the forums for an answer to this problem and only finding old (or unresolved) mosts I figured it was time to raise this again.

Mattermost desktop app is not making sounds when new messages come in. The red badge in the dock DOES appear, so notifications of some sort are getting through.

Mattermost Version: 10.11.2
Database Schema Version: 141
Build Number: 17123712923
Database: postgres

macOS Sequoia 15.5
Mattermost Desktop app 5.13.0

Sound is not muted (got to cover the obvious stuff first)

Sound settings in Mattermost app: on

Sound settings in system prefs: on (general and app-specific)

Sound settings in mattermost and system prefs have both been cycled off/on

Ideas?

UPDATE: In the desktop app: Settings (gear icon) → Notifications → Desktop Notification Sounds we needed to edit and assign a sound. Not sure why this was broken but that fixed the issue.