UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.106 Safari/537.36

Example URL:
http://output.jsbin.com/vicopowaha/10

Steps to reproduce the problem:
1. Create a relatively positioned div with margin
2. Create an absolutely positioned div with auto top/left
3. Notice that the absolutely positioned div is affected by it's relatively positioned sibling. 

What is the expected behavior?
Only ancestor nodes (not siblings) are expected to be used to calculate the actual value of top:auto; and left:auto for absolutely positioned elements. 

What went wrong?
Chrome is identifying the sibling node as an ancestor node and including it's margin value in the calculation of the absolutely positioned top:auto and left:auto values.

Does it occur on multiple sites: Yes

Is it a problem with a plugin? No 

Did this work before? N/A 

Does this work in other browsers? No 9.0.3

Chrome version: 51.0.2704.106  Channel: n/a
OS Version: OS X 10.11.3
Flash Version: Shockwave Flash 22.0 r0

https://www.w3.org/TR/css-position-3/#abs-pos
For box offset top (the value of auto): "For absolutely positioned elements whose containing block is based on a block-level element, this property is an offset from the padding edge of that element."