I haven't done anything to my gps/navigation and my location has been way off lately too. I'll correct the location and the next day, same problem again...very annoying.

 

Question does the location correct it self automatic or do you have to manually do it? Also have you done any audio up grades? It could possible multiple things connections or the fin on the roof but if it corrects its self might be the place its stored or parked or might need a map update. Just some ideas hope you figure it out. And when you do post it for anyone else looking for answer.