I just got my D4 about 2 weeks ago. I normally have the phone set to vibrate only during the day, but on the weekends, I've been noticing that my phone will randomly sound my text messaging notification tone. Thinking I've received a text message, I take my phone out of my pocket to check it, but alas, no text or voice message is there. In fact, I have no notifications for anything whatsoever. I'm on an unrooted D4, and I'm on version 6.13.219. Has anyone else experienced this issue at all? I've also noticed the phone doing this at night while it is charging, however I have the "Full Battery Notification" turned off.