This bug pertains to variable product images.
When a variation image is displayed in the main image container, the magnifying glass link in the top left of the image links to the featured/default image for the product.
This is the incorrect behavior, when viewing a variation image users are of course expecting to view a large version of the same image when clicking on the magnifying glass.
This bug can be seen in action in the neighborhood demo here (select a different color and then click on the magnifying glass) – http://neighborhood.swiftideas.com/product/new-balance-variable-demo/
Could you amend the theme so that when a variation image link is clicked, it links to a large version of the same image?