Image maps & iPhone issue

Hi – I’m not sure if this is related to the Responsive theme or what, but I’m not sure where to ask.

The site I’m working on has an image map that’s working on my Mac (Chrome & Safari), but it’s not working when I check it on my iPhone – the coordinates for the image map seem to have shifted.

Not sure if it’s related to me using retina-ready images (@x2) or not.

Any ideas, or even ideas of a better place to ask this question if this isn’t the right forum?

Dev site is: https://www.dozenablemen.com/wordpress_dev/portfolio

Thanks!