My calender was not syncing so I tried to delete my Google account and re-add it figuring that would clear the problem. I had to do a factory data reset to delete the account resulting in me needing to completely re set up my phone (screens, apps, etc) well it fixed my calendar sync problem but I forgot to turn off 4G. I keep it turned off because we don't have real good coverage here yet and I want to conserve battery. Anyway... while out on service calls today using maps/navigation it would not find the address I was looking for the "searching for" spinner just kept going. I noticed I did not have a data connection so I tried the old "Toggle Airplane" fix and it came back. I received a call while driving and had to go back to maps when done and found the data connection was now 4G but not blue and it was having trouble finding the address again. I was getting locked between a nearby WiFi connection, 3G and 4G and not allowing data to resume without an "Airplane Toggle".
I went in and turned off 4G and it seemed to work better... I hope this isn't an issue when they bring more 4G towers on line as the phone is useless in 4G mode as it is now.