Browser zoom breaks layout

[wouterrutgers]

I am using Masonry to make 3 columns, this works fine in all browsers. However when I change the zoom level in Safari (tested this on safari 6-9) it puts everything in 1 column. Zoom level doesn't make any difference in other browsers, just safari.

You can see what happens in the codepen below, it isn't the exact same problem. But it's not making the number of columns as you'd expect.
http://codepen.io/anon/pen/epLwrE

[Arcrammer]

I can confirm the behaviour is consistent throughout Safari, Chrome, and Firefox.

Are you perhaps doing any math to calculate the column-width?

[CartesianDuelist]

It's a webkit issue, not just Safari. The issue is NOT present on Firefox.