Markdown code blocks lose carriage returns when edited via CMS

[fool]

- Do you want to request a feature or report a bug?

bug

- What is the current behavior?

when viewing markdown in the CMS, the rendered version of code blocks seems to collapse all whitespace to a single space, be it carriage return, tab, or spaces.

- If the current behavior is a bug, please provide the steps to reproduce.

you can demonstrate without saving anything. view a post in the CMS:

https://www.netlify.com/admin/#/collections/blog/entries/2015-10-1-a-step-by-step-guide-middleman-on-netlify

..which is rendered properly in its current form:

https://www.netlify.com/blog/2015/10/01/a-step-by-step-guide-middleman-on-netlify/

The editor shows and saves the text correctly:

...but the rendered version loses that spacing:

(both shots are from the CMS, edit and preview windows that are side by side during editing)

- What is the expected behavior?

spacing is preserved.

- Please mention your node.js, and operating system version.

Built on netlify, node 6.9.1/ubuntu 14.04, used via https://www.netlify.com/admin