That's because Australia drifts northeast about 70 millimeters every year, according to Popular Mechanics, and since the last time Australian GPS coordinates got an update in 1994 the continent has moved 1.5 meters, or about 5 feet.
We can thank naturally occurring tectonic shifts for this phenomenon. As the Earth moves, mapping information gets less reliable, and eventually the difference becomes big enough to notice.
This may not be a big deal for everyday users getting from Point A to Point B, but imagine the chaos an irregularity like this could cause in a world with self-driving cars that depend on location accuracy.
The Australian government is working on the issue: Geoscience Australia is on a mission to get the national coordinate system squared away.
Erika Owen is the Senior Audience Engagement Editor at Travel + Leisure. Follow her on Twitter and Instagram at @erikaraeowen.