easeBack functions not working on Safari

This is a weird issue. While the easeBack functions (in/out/inout) seem to work on the front page (dot preview), they don't work when you try to view the dedicated page for it. The transition works, but the element will stay on position 0 (both in the beginning and the end) where the math function produces negative numbers (the "back" part).

This happens on both safari for mac and iOS.

What is even more weird, is that the very same function on cubic-bezier.com works perfectly.