Cant select variation in checkout

Hello,
I am using a WooCommerce Extended Coupon Features PRO
It allows me to offer a free gift in checkout from my product list.
i am using Villatheme product variations swatches as well.
It seems that when product variation swatches is active, the box for selecting the color variation disappear.
the other developer suspect the required scripts for the variation swatches aren’t loaded on the checkout/cart page.