This is a probably not a bug, more a quick support request because I'm getting nowhere.

On Android 12, with Battery Saver mode enabled (normal, not Ultra), SunTimes alarms do not go off. In Settngs>Apps>SunTimes>Battery, I have of course selected "Unrestricted".

Is there a remedy?

I understand it is something to do with the Android system timer. For instance, sometimes, when I turn on the screen, the most recent missed alarm will go off!

NB: anecdotally, apps seem to resist Android killing them if they have an active notification. On a previous Android version I remember seeing a persistent "alarm bell" icon when a SunTimes alarm was active. Not on Android 12, even though I have allowed all SunTimes notifications. Is that to be expected?

Thanks so much for advice.