I have DND scheduled to turn on every night. I get a notification and sound every night when it turns on. I have gone into Settings>Notifications>Do Not Disturb>Hide Notifications>Hide Notifications and turned on Hide All. I still get the notification and sound when it turns on. At the bottom of the screen in the settings hide page it says "Critical notifications about phone activity and status will never be hidden". Does this mean you can not turn off the DND notification now? So if I fall asleep early my DND wakes me up to tell me I will not be woken up!
@userzdF4GnjBCf I have use automatic DND every day and have never received this alert. I get a banner in the notification area but no sound.
Are you doing this directly from notifications -> DND or are you using a routine?
Can you post a screenshot of this alert?