title: Very strange chrome bug with z-index and position:fixed
body: <p>I've to do a very quick frontend build on a temp site,</p>
  
  <p>There's an odd bug that only appears occasionally in Chrome, and it's the sticky header that is sometimes positioned underneath the content.  It has a z-index of 10, none of the content that has positioning is has a higher z-index than this.</p>
  
  <p>The strangest thing is that it only appears occasionally and not everytime, like 5-10% of the time, which makes testing very difficult.</p>
  
  <p>I tried removing the 3d transform on the nav element but the bug still persists.  It seems it is some kind of rendering issue but It's critical I find out the cause because we cannot launch with a bug like this for obvious reasons.</p>
  
  <p>link: 
  <a href="http://wasabiadmin.se/getillbaka/" rel="nofollow">http://wasabiadmin.se/getillbaka/</a></p>
  
  <p>I can't really post any code because I am not sure what could be causing it.  I don't think it would be helpful to post reams of code in this instance.
  The elemement with the bug has the class of .navbar located as a descendent of .site-header for quick viewing in Chrome Dev tools.</p>
  
  <p>If anybody can shed any light on this really unusual behaviour I'd very much appreciate it.</p>