Weird Chrome issue (possible jquery conflict?)

Hi guys
I have a site using jQuery for a 'sticky nav' and also Flexslider here:
http://madebymartin.co.uk/

In Chrome, the links in the main nav visually disappear (the markup is still there) when the 'fixed-nav' class is applied to the menu div (when you scroll down the page)..

If I remove just the Flex slider script (eg here: http://madebymartin.co.uk/portfolio/germaine-de-capuccini/) or just the sticky nav script, the problem goes away. The problem does not happen in Firefox or on Safari on the iPad or iPhone - I've only seen it in Chrome so far...

Any ideas?!
Hope you can help

Thanks
Martin