UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/57.0.2987.98 Safari/537.36

Steps to reproduce the problem:
1. Go to the following link :https://www.webcomponents.org/element/PolymerElements/paper-radio-group/demo/demo/index.html
2. Press Tab until you are inside radio button in focus mode
3. Press Escape so you are on browse mode
4. Use up/down arrows to have NVDA read the choices
3. 

What is the expected behavior?
with each arrow up/down I would expect only one choice being read.

What went wrong?
up arrows reads whats before the radio button 
if you do arrow down then, it will read all of the radio buttons all at once
another arrow down would read whats below radio group.

Basically radio buttons are being read horizantally.

Did this work before? N/A 

Chrome version: 57.0.2987.133  Channel: n/a
OS Version: win 7 
Flash Version: Shockwave Flash 25.0 r0

If you look at w3 example:
https://www.w3.org/WAI/tutorials/forms/grouping/
you can arrow up/down between the choices are read them one by one