Upon building a wocommerce based site build on Bootstrap 4.1.3 or above I noticed there was a conflict of bootstrap 4 based classes : col-1 and col-2 and woocmmerce based classes : col-1 and col-2 set which affects the cart , so upon looking into this issue there is a simple fix which can be applied

on your theme or the child theme in the /style.css place the following code to rectify this error (Based on development notes for bs4 woocommerce theme)

/*fix wo conflict of columns */
.woocommerce .col-1, .woocommerce .col-2{ max-width:none;}

.woocommerce-billing-fields .form-row, .woocommerce-shipping-fields .form-row,.woocommerce form .form-row {
display: block;

.woocommerce .col2-set .col-1, .woocommerce-page .col2-set .col-1,.woocommerce .col2-set .col-2, .woocommerce-page .col2-set .col-2 {
max-width: unset;