This one got me puzzled (client site): When on the shopping cart page, I am unable to update the quantity in cart of any given product. I can change the quantity in the box but pressing the update icon does nothing.

Site is bubs2grubsknitting[dot]com[dot]au
ZC version 1.5.5e
PHP 5.6.30

I have scoured through virtually every similar thread dealing with this issue, to no avail.

Compared the files

includes/modules/pages/shopping_cart/header_php.php
includes/templates/bubs/template/tpl_shopping_cart_default.php

to relevant stock files and can't find any differences (other than css / display changes in the override template file).

Thanks guys