This is a head's up for Simon or Hans.
There's some weirdness happening with some Chrome browsers. It's not all Chrome; and the error isn't confined to Wizzley. There's more information here.
However, I have two friends for which this is happening on Wizzley. They can see the profile pages just fine, but as soon as they click on an article, the URL gets a random /undefined added to the URL. This naturally sends them straight to a 404 page.
It seems that the issue may be a third party plug-in in Chrome, thus nothing to do with Wizzley. But both of my friends say they haven't got that plug-in. It's happening to both of them on a number of websites, not just ours.
I just wanted to give you the head's up, in case you're seeing the error logs and wondering, or you need to be in contact with someone it's happening to. Of course, the ideal situation would be if something could be added to the javascript, which would over-ride the Chrome bug. I don't know if that would clog your code though.
Good luck!
yours
Jo
xxxxx