Height not being set for container if box-sizing is not content-box and element has border/padding

Hello,

I have a container height issue with all the tests I have been able to do on Edge.
The polyfill gives a position: absolute and fixed height on each grid item, but the container doesn't compute it's children's height, so they overflow.

Codepen : http://codepen.io/raphaelgoetter/pen/ZQLBxd
Screenshots : http://www.hostingpics.net/viewer.php?id=700041edgepolyfill.png