A few days ago my Lumia 950 (AT&T) acted up, and now for some reason I get absolutely zero sound on texts when the phone is locked. Let be more clear: if I am using any app (or home screen, start screen, etc) and I get a text, the phone vibrates and dings just fine. When I set the phone down and it gets locked (either timeout or manual lock) I get no sound or vibrate on text notifications. I still get sound/vibrate on certain other notifications.
The notification shows up on the glance screen, and in my action menu, but it makes no sound/vibration when the phone is locked. This is a seriously large issue that's really irritating me. Yes, the "Ringer + Notifications" volume is all the way up. I've tried dropping the volume down to "Vibrate" and then back up to "10", but it still has the same issue. It seems to only be text messages that do it, but I don't get notifications for many other things (except email which I have sound turned off for).
I have done several soft-resets (both by pulling battery and using the power button) and nothing has worked.
Phone: Microsoft Lumia 950
OS Build: 10.0.14393.67
Firmware Revision Number: 01078.00038.16025.39033
The device did an update this morning, problem persists.