I think it would be good to start a catalogue of weird "failed GPS paths" patterns. The one above could be called "right way, wrong door". The other day I Geneva, while going to a seminar, my iPhone GPS gave me this curious set of information that I liked a lot. I was looking for a building I've never been into and used the GPS device to help me.
The "path solution" it gave me is the one above, strip naked in terms of urban elements (for some reasons, it's only a grid as if I was playing "Space harrier"). I simply had to go back on the avenue and find the entrance on the other side of the building. It left me wondering about the way navigation database are aware of building entrance, surely a parameter that add a layer of complexity.