Can you send an url + coupon code so I can take a look at the issue on your cart page?
About the checkout page, we did this on purpose to prevent too much distraction on the checkout page. Furtunately you can achieve this by overriding a template file.
Copy wp-content/plugins/woocommerce-auto-added-coupons-pro/templates/checkout/select-free-product.php to wp-content/themes/YOUR_CHILD_THEME/woocommerce-auto-added-coupons/checkout/select-free-product.php and replace this:
foreach ( $coupons_form_data as $coupon_code => $coupon_form_data ) :
if ( empty( $coupon_form_data['selected_quantity'] ) ) {
$template->render_template( 'coupon-select-free-product.php', $coupon_form_data );
}
endforeach;
with this:
foreach ( $coupons_form_data as $coupon_code => $coupon_form_data ) :
// if ( empty( $coupon_form_data['selected_quantity'] ) ) {
$template->render_template( 'coupon-select-free-product.php', $coupon_form_data );
// }
endforeach;
(Notice the two commented lines)