Alarm volume changes on its own Something keeps lowering my alarm volume. I keep it at about 70% because I can be a heavy sleeper at times, but I keep finding that it's been lowered to about 40%. This has been going on daily for months. (One time it turned itself to silent and I slept through my first class)

Any ideas as to what's causing this or how to fix it?

EDIT: I've realized that it would probably be useful to talk about some of my settings.
I have Do Not Disturb scheduled for "Priority Only" from 10pm to first alarm daily.
I keep my ringer on mute or the first/second setting.
So, I've had this problem for a while as well. What I came to realize was that my sleepy-brain would hit the volume rocker to adjust the volume of the alarm while it was going off. Usually, this was to adjust the volume of my music to a more bearable level to wake up to once my phone was in-hand. But this also had the side-effect of adjusting my alarm volume to a point where next time it goes off, it's way too quiet.

I fixed this problem by downloading an app called MacroDroid. I set up a macro that executes each night at 10 pm. The macro starts by setting the alarm volume to 80%, pops a notification up that says "Don't forget to set your alarm!" And when the notification is clicked, it takes me to the Clock app to set my alarm. 

It's a bit of a workaround since it uses a third-party app, but it's been a huge quality-of-life adjustment for me so I figured I'd share.