Another anecdote: my wife and a colleague at work (so 2 different people I know) have Xiaomi Note fives, and this model kills the stock alarm clock app! Regularly for both these people the alarm does not go off. My wife keeps an old Nokia candy bar phone around as a backup alarm it has happened so often. There's a workaround, maybe just placebo?, for this too: you can go to the recent apps screen and pin the app. But any kind of system update seems to undo the fix. I imagine your audible lock-screen widget will have the same issue, that system updates break the fix, and MIUI updates quite regularly.
I have a Xiaomi A1, with a more stock version of Android, and so far this has not been an issue. But I noticed in the recent Pie update that it mentioned "battery improvements". I've had no problem with battery before now, it lasts all day easily and I get home with 70% or so. I hope it doesn't start killing the alarm clock at night, when it's plugged in to charge, just to save battery.
I have a Xiaomi A1, with a more stock version of Android, and so far this has not been an issue. But I noticed in the recent Pie update that it mentioned "battery improvements". I've had no problem with battery before now, it lasts all day easily and I get home with 70% or so. I hope it doesn't start killing the alarm clock at night, when it's plugged in to charge, just to save battery.