iPhone alarm going off at randomly wrong times.

I have recently installed iOS 15.3.

Since then I have set my alarm to wake up at my usual time every morning at 7:50 AM. Over the last eight days, on three occasions the alarm did not go off at all and when I open the phone and checked the little slider button had turned off. On three days it worked fine.

In two of the days the alarm woke me up exactly 35 minutes earlier than I had set. I double checked and triple checked last night that I set the alarm for 7:50 AM and this morning the alarm went off at 7:10 AM.

I believe this is a bug in iOS 15.3 since this problem started after installing it.

Do I have to wait for a new update?