Hi,
First of all, keep this in mind.. You are still using Virtuemart Component to process shopping cart functions.
Our template is just style pages "visually". So backend functions that go behind the scene is all about the core functions of Virtuemart. Our template are not allowed to change/modify/tweak those core functions.
The problem you are talking about is something to the slow "AJAX" processing or failure AJAX processing. Usually the page should be fully loaded before clicking the add to cart button, and JSON through AJAX loading takes little time (1-2 seconds, or sometimes up to 4 seconds depends on your server response speed)
The correct place you need to open a thread is
forum.virtuemart.net
raise a complain about slow/failure "add to cart" functionality and request an improvement for the future VM versions.
BUT alternatively, you can disable the AJAX loading functionality when the product is added to cart through:
VM Backend > Configuration > Checkout
and disable
Display modal popup upon 'Add to cart'
So once the product is added to cart, the website will be redirected to shopping cart directly. There will be no modal popup and AJAX loading for adding product to shopping cart module which creates delay. so you would minimize the losing conversion.
Regards.