Over the last few days, very now and again, my M8 notifications can't be heard. When I check the notification volumes, they are all set to maximum, and my sound profile is still set to normal, but when I receive a text, or an alarm goes off, the phone just vibrates. I have to restart the phone to correct it, but at a random time, it'll go back to no-volume notifications. This might have all started after the recent OTA firmware update.
Can anyone help?
P.S. - Phone is not rooted.