I've been noticing this too. I'm in a strong 4G area and my 3G service just disappears, turns into the little Edge O symbol when it shouldn't be. I've also had tons of calls that aren't coming in. I login to a call service for work sometimes and all of a sudden I'll get 3 emails with 'missed call' notices and my phone will be sitting right in front of me and will not have any missed calls at all on it or never have rang. I thought it was actually my phone so Verizon sent me a replacement iPhone and it's still doing it. Not a happy camper.