I Phone 11 self lowering sound volume
Why does my I Phone self lower the sound volume?
iPhone 11 Pro, iOS 14
Did you notice whether this happens only when your iPhone is in your hand(s) and when you are looking at it?
This is part of the Attention Aware Feature of the iPhone. When the iPhone has your attention while you are looking at the screen (typing, reading websites or working with an app), then it automatically reduces the sound because it knows you are looking right at it so no need to issue loud notifications.
You can turn this feature off if you want by opening Settings ➔ Accessibility ➔ Face ID & Attention ➔ Attention Aware Feature set this to OFF.
Axel F.