I've noticed a couple of issues but not sure if they're related or not. I often notice, without moving the phone much, the signal will fluctuate greatly especially when coverage is moderate. It will go from about three bars to no coverage without moving. All to often I'll be sending a text message with android warning me that there is no network coverage when I had good coverage just a second ago. Sometimes after turning off, or leaving, WiFi coverage I notice that the signal bar will constantly cycle from grey to h/grey to h/blue then back to grey and do that constantly until i reboot the phone.