README file with markdown preamble is not parsed anymore (BB-4431)

With the latest UI updates, a README file with the markdown comment preamble is not parsed anymore.

Here's an example repository: https://bitbucket.org/anhero/redboxapp

Here's the preamble used
{{

}}

as recommended here
http://confluence.atlassian.com/display/BITBUCKET/Displaying+README+Text+on+your+Bitbucket+Source+Tab

Thanks!