Only 1 item added to cart and error when updating quantity in cart

-- HikaShop version -- : 3.0.0_2017-02-22_17-00-15
-- Joomla version -- : 3.6.5
-- PHP version -- : 5.6
-- Browser(s) name and version -- : Chrome 56.0.2924.87
-- Error-message(debug-mod must be tuned on) -- : Fatal error: Call to a member function checkSize() on null in /var/www/vhosts/iafdesign.net/httpdocs/dev/3lab/components/com_hikashop/views/checkout/tmpl/show_block_cart.php on line 87

1. If more than 1 item is selected, only 1 is shown in the basket, this happens with all items.
2. If you then go to checkout and update the quantity, then it errors:

Notice: Undefined property: CheckoutViewCheckout::$imageHelper in /var/www/vhosts/iafdesign.net/httpdocs/dev/3lab/components/com_hikashop/views/checkout/tmpl/show_block_cart.php on line 90

Fatal error: Call to a member function checkSize() on null in /var/www/vhosts/iafdesign.net/httpdocs/dev/3lab/components/com_hikashop/views/checkout/tmpl/show_block_cart.php on line 90

3. The latest version of Hikashop has also produced errors in the back-end configuration/advanced/cart retaining period and frequency of check for the carts settings:

Notice: Undefined variable: return in /var/www/vhosts/iafdesign.net/httpdocs/dev/3lab/administrator/components/com_hikashop/types/delay.php on line 120

Notice: Trying to get property of non-object in /var/www/vhosts/iafdesign.net/httpdocs/dev/3lab/administrator/components/com_hikashop/types/delay.php on line 120

Please note we are using the legacy setting for 'Add to Cart' as it needs some rewriting of CSS for this to work for us.

Hi,

1. It's probably linked to the legacy setting and the view overrides you have on your end. Hard to say without even looking at the page and analyzing the situation there. But we don't have the problem on our end.

2. and 3.
We've added a patch in order to fix that problem. Download again the install package on our website and install it on yours and that will fix the issue.