Ever since I updated to 11.4.1 (iPhone 7), my alarm on the built-in alarm app hasn't been working consistently like it should. Some mornings it goes off at the correct time, other days it doesn't. Last week it went off at 5:10 am even though it was set for 5:00 am. This morning, I happened to wake up 2 minutes after my alarm should have been going off and noticed that it wasn't. When I picked up the phone the alarm suddenly jumped to life and started going off. I've used the iOS alarm for years without any issues. Not sure how to fix this other than maybe a restart of my phone. Any thoughts?