I'm looking for the setting for notification sounds. When I receive an iMessage or text message, my phone only notifies me with a tone when the phone is unlocked. When the phone is locked, nada. I'm probably missing something or something got moved when I installed the Beta.
Any thoughts?
I'm having the same issue. New iPhone 7 Plus and joined the iOS 12 Public Beta Stream.
When anyone sends a SMS or iMessage and the phone is locked, I get no audio notification that I received a message. If I press the home button, I can see I received messages, but no notification. And like you said, if the phone is unlocked and just sitting at the home screen, the notification sounds work perfectly normal.
Ring/silent switch is set to normal position, volume/ringer turned all the way up, Do Not Disturb is turned off.
Anyways, I reported the feedback to Apple.