Free Gifts for WooCommerce

I’m using this plugin and WPML on my website. If you’ve a free product added in to your cart and then try to change the language, it gives critical error.

The error in debug is below:

Stack trace:
#0 /home/fdh2zyqsf0jx/public_html/wp-content/plugins/free-gifts-for-woocommerce/inc/frontend/class-fgf-rule-handler.php(541): FGF_Rule_Handler::bogo_rule_products()
#1 /home/fdh2zyqsf0jx/public_html/wp-content/plugins/free-gifts-for-woocommerce/inc/frontend/class-fgf-rule-handler.php(174): FGF_Rule_Handler::matched_rules()
#2 /home/fdh2zyqsf0jx/public_html/wp-content/plugins/free-gifts-for-woocommerce/inc/frontend/class-fgf-rule-handler.php(224): FGF_Rule_Handler::prepare_matched_rule_gift_products()
#3 /home/fdh2zyqsf0jx/public_html/wp-content/plugins/free-gifts-for-woocommerce/inc/frontend/class-fgf-gift-products-handler.php(390): FGF_Rule_Handler::get_automatic_gift_products()
#4 /home/fdh2zyqsf0jx/public_html/wp-content/plugins/free-gifts-for-woocommerce/inc/frontend/class-fgf-gift-products-handler.php(179): FG in /home/fdh2zyqsf0jx/public_html/wp-content/plugins/free-gifts-for-woocommerce/inc/frontend/class-fgf-rule-handler.php on line 878
[05-Sep-2022 11:36:08 UTC] PHP Notice: Undefined index: 2dea61eed4bceec564a00115c4d21334 in /home/fdh2zyqsf0jx/public_html/wp-content/plugins/wallet-system-for-woocommerce/public/class-wallet-system-for-woocommerce-public.php on line 690
[05-Sep-2022 11:36:08 UTC] PHP Notice: Trying to access array offset on value of type null in /home/fdh2zyqsf0jx/public_html/wp-content/plugins/wallet-system-for-woocommerce/public/class-wallet-system-for-woocommerce-public.php on line 691