I suspect this is a problem of fragmentation on Android. I've had issues when I tried other Clock apps than the Google one. Alarms would not be triggered for various inexplicable reasons. Or they reset if the launcher crashed for whatever reason. I don't have the time and energy to test this simple function that I rely on quite heavily. And that's why I stick with the stock Google app because it has never failed me personally no matter whose manufacturer's version of Android it ran on.