@baris thanks. I realised there's some issues with redactor munging the data.
When code is insered inside a <pre/> block, switching between HTML and WYSIWYG views will munge the content to HTML entitites.
You can recreate this issue on this page:
http://imperavi.com/redactor/examples/typography/

Switch to code view and add some HTML inside the <pre/> block. I entered:
<p>test</p>
Switch to WYSIWYG and back to code and it has been replaced by:

This breaks the ability to parse that code later with syntax highlighters.

I've raised it with Imperavi.

@julian Greate! I will push my code plugin in to highlight.js

@nik This was the board I tested it on. 😆 I'm not sure if @julian can shed some light on this as something isn't right with your experience and I'm not sure what would cause these things to happen. It's not your build of NodeBB, it's not one browser or the other as it happens on both Desktop & Mobile, the only thing left is your internet connection, but I don't know whether xhr-polling or websocket issues would cause it.