Does this only happen when the iPhone is connected to a certain Wi-Fi network? Maybe it's connected to a Wi-fi router that was previously in another state.
Take a look at this Apple doc -> iOS 6: Understanding Location Services
Crowd-sourced Wi-Fi and cellular Location Services
If Location Services is on, your device will periodically send the geo-tagged locations of nearby Wi-Fi hotspots and cell towers in an anonymous and encrypted form to Apple, to augment Apple's crowd-sourced database of Wi-Fi hotspot and cell tower locations. In addition, if you are traveling (for example, in a car) and Location Services is on, a GPS-enabled iOS device will also periodically send GPS locations and travel speed information in an anonymous and encrypted form to Apple, to be used for building up Apple's crowd-sourced road traffic database. The crowd-sourced location data gathered by Apple does not personally identify you.