I am experiencing the same problem. My maps coordinates also take me off the coast of Ghana Africa. But if you zoom out -- ALL the way out, there actually is a red position marker/thumbtack at your actual location. Zoom in on that, and BAM, it's dead on.
So really for some reason, maps is not automatically centering on the coordinate, though it is putting a dot there.
Bizarre.
On my mac, I can set safari debugging on and user agent to iPhone, then the map DOES center in on the coordinate, using the same exact input string given to apple maps. So it does not appear to be a google problem, seems to be apple maps application problem.
APPLE, PLEASE FIX, this one should be easy.
thanks