[iMore Question]

Since upgrading to ios 12 my iPhone 7 Plus, at seemingly random intervals, will behave as if Do not Disturb mode has been triggered. Although there is no half-moon icon and Do not Disturb is certainly not engaged, incoming messages and emails have ceased triggering notifications when the phone is locked and idle. In contrast, when the phone is unlocked and in use, notifications arrive as expected (banner / tone / vibration). Also, notifications arrive on apple watch just fine. Notification setting for watch is "mirror iphone"

[Ledsteplin]

Welcome to iMore! You might try turning DND off completely. Then do a hard reset.
7 Reset
Hold the power/wake button and the volume down button at the same time until the Apple logo appears. Then release.
Then set up DND again and see what happens.

You might also try Reset All Settings.

Go to Settings >General >Reset >Reset All Settings. This resets to default everything in Settings, including notifications, alerts, brightness, and clock settings like wake up alarms.

[A Michaels]

Hi. OP, here. Tried all of that. Multiple toggles / reboots / resets / etc. DND is off completely and still the issue persists.

[Tartarus]

Hi. OP, here. Tried all of that. Multiple toggles / reboots / resets / etc. DND is off completely and still the issue persists.

When the phone is locked the Apple Watch will take over the notifications and not your iPhone.
That’s how it’s supposed to be.

When I hear a notification on my watch and my phone is within hand reach I just look on my phone to see what the notification is.

[akavbb]

I have experienced the same problem and I do not have Apple Watch. There were times that I was receiving phone calls and the phone was not ringing.