Attribute Drop Down Disabled

I’ve updated WP and the jigoshop version to be the latest and I’ve noticed that for second placed attributes it’s not showing the drop down and the code shows that’s it’s disabled. Not quite sure how to rectify this.

If you go to: http://www.jamieinglisjewellery.co.uk/product/two-piece-flower-pattern-pendant you’ll see there are two variations for decoration and chain length. If you select the decoration and choose something and then try to open up the chain length it’s not working correctly. I’ve not changed anything to any settings as far as I’m aware. Any ideas what’s causing this?

Thanks!

https://ww.wp.xz.cn/plugins/jigoshop/