bing map pin sliding

When using the Icon Field Map Property on a bingmap webpart, the pins will be further and further off position depending on how far out the zoom level is. When zoomed all the way in, it will be perfectly accurate. As I zoom out, it will become less and less accurate, hitting higher and higher on the map. This behavior only happens while the Icon Field Map Property is used. The image I use for the Icon Field is exactly the same dimensions as the default pin, and has the same pixel for the tip of the pin image. As a test, I made the default bing pin image the image I was using for Icon Field, and once again, the pin will slide off it's mark exponentially more as the map is zoomed out. Once again, if the Icon Field is left blank, the pins are always positioned correctly. Any suggestions on why this may be or what I can do to work around it?