I have a brand new iPhone 12 with iOS 14.2.1 it has DND scheduled, and DND set to off. Yet the phone sets to silent when screen is locked. This happened on older phones and was fixed (iPhone 8). I migrated from iPhone 8 to iPhone 12, this wasn’t an issue on the iPhone 8 with the same iOS. But it now seems to be an issue on the iPhone 12. I will raise a call to Apple but feel it’s a bug.
You can report what you think are bugs, here: https://www.apple.com/feedback/
Also, you want to check your Bedtime settings ... if you had set up Bedtime, you are also perhaps setting up DND to be activated ... Use Bedtime to track your sleep on your iPhone - Apple Support
You can report what you think are bugs, here: https://www.apple.com/feedback/
Also, you want to check your Bedtime settings ... if you had set up Bedtime, you are also perhaps setting up DND to be activated ... Use Bedtime to track your sleep on your iPhone - Apple Support
I needed to set the haptic settings and reset the volume and change by button. Which seems to have resolved the issue. I raised a ticket and got that advice.
iPhone 12 turns to DND a when locked even when feature is not activated
