Navigation Continuing When Car Stopped

In general I've been very happy with the GPS/navigation. However, on two occassions I've had the navigation keep on going even though my car is stopped (not 100% sure if it was catching up or it continued on the route from the point I stopped - exited out and restarted navigation and it was fine). Both occassions happen when I was in the same general location in the center of a town - not an extremely big city (approx 10 sq mile) and most buildings under 8 stories. Anybody else experience this?