I started getting random notification sounds the same day I upgraded to ICS. There will be no actual notifications, but the notification light will blink until I pull the notification window down. I have examined every app and every setting I can think of and made sure the notifications are off. I have already reported noticing a substantial drop in signal strength since the upgrade. I am trying to troubleshoot the notification problem a bit more before reporting it. Not happy with ICS upgrade so far. Anyone else experiencing the phantom notification sounds?