UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.95 Safari/537.36

Steps to reproduce the problem:
1. http://codepen.io/derz/pen/YNXzGW
2. Hover on sticky element
3. Sticky Element jumps (N pixel of box-shadow) during the transition of the child 

4. scroll further down to the second sticky element (this time without box-shadow)
5. hover it
6. second element stays in place

What is the expected behavior?
Element should stay in place just like the second sticky element.

What went wrong?
Sticky element moves N pixel (based on the box-shadow blur-radius) in x and y direction.

Did this work before? N/A 

Does this work in other browsers? Yes

Chrome version: 57.0.2973.0  Channel: stable
OS Version: OS X 10.12.2
Flash Version: Shockwave Flash 24.0 r0