Timer notification has no sound after closing the app (Android)

A timer rings while Gratin is open or still running in the background, but after dismissing Gratin from Android’s recent-apps screen it only shows a notification, without an alarm sound. The same phone sounds an alarm in another cooking app after dismissal. Reported on 0.4.0 by a beta tester. The timer tray and background timekeeping shipped, but audible alerts after dismissal need a separate fix.