Cynanogenmod is an aftermarket firmware (typicically known as a custom ROM) for Android. It adds many new features and makes a lot of improvements, especially for the power user. Some of these improvements are in the alarm clock app.
I’ve been using Cyanogenmod for years. Recently I noticed that sometimes the alarm clock will go off in the morning, then snooze by itself without me touching it. I thought this would seem like an obvious bug and get fixed right away, but it hasn’t. This morning it finally hit me. I now know the reason for this unexpected behaviour.
The screenshot above shows a setting in the app to snooze alarm when the phone is shaken.
The next screenshot shows a setting to vibrate the phone when the alarm goes off. I’m sure you can put the pieces together yourself at this point.
You guessed it. The vibration of the phone can cause enough movement to trigger the snooze of the alarm clock. Simply disable one of these settings and it won’t happen anymore.