My S series phone had this annoying shrill bicycle bell notification at random timings even at 4 am! My A54 just had this same notification sound and there is no notifications from my apps per my notification history. Putting phone on silent mode does not disable this only switching off the phone does. Does anyone know the source of this and how to disable it? I've been using Samsung phone for years and only experienced this about 5 months ago. Extremely annoying.