PHP 8 fatal error in woo checkout field editor pro

That is the whole log

[02-Jun-2022 12:18:40 UTC] PHP Fatal error:  Uncaught TypeError: array_merge(): Argument #1 must be of type array, bool given in /wp-content/plugins/woo-chec
kout-field-editor-pro/public/class-thwcfd-public-checkout.php:494
Stack trace:
#0 /wp-content/plugins/woo-checkout-field-editor-pro/public/class-thwcfd-public-checkout.php(494): array_merge()
#1 /wp-includes/class-wp-hook.php(307): THWCFD_Public_Checkout->display_custom_fields_in_emails()
#2 /wp-includes/plugin.php(189): WP_Hook->apply_filters()
#3 /wp-content/plugins/woocommerce/includes/class-wc-emails.php(488): apply_filters()
#4 /wp-includes/class-wp-hook.php(309): WC_Emails->order_meta()
#5 /wp-includes/class-wp-hook.php(331): WP_Hook->apply_filters()
#6 /wp-includes/plugin.php(474): WP_Hook->do_action()
#7 /wp-content/plugins/woo-rfq-for-woocommerce/woocommerce/emails/customer-rfq.php(109): do_action()
#8 /wp-content/plugins/woocommerce/includes/wc-core-functions.php(345): include('...')
#9 /wp-content/plugins/woo-rfq-for-woocommerce/includes/classes/emails/class-wc-email-customer-rfq.php(152): wc_get_template()
#10 /wp-content/plugins/woocommerce/includes/emails/class-wc-email.php(545): WC_Email_Customer_RFQ->get_content_html()
#11 /wp-content/plugins/woo-rfq-for-woocommerce/includes/classes/emails/class-wc-email-customer-rfq.php(92): WC_Email->get_content()
#12 /wp-includes/class-wp-hook.php(309): WC_Email_Customer_RFQ->trigger()
#13 /wp-includes/class-wp-hook.php(331): WP_Hook->apply_filters()
#14 /wp-includes/plugin.php(474): WP_Hook->do_action()
#15 /wp-content/plugins/woo-rfq-for-woocommerce/includes/classes/emails/class-wc-email-rfq.php(95): do_action()
#16 /wp-includes/class-wp-hook.php(307): WC_Email_RFQ->send_transactional_email()
#17 /wp-includes/class-wp-hook.php(331): WP_Hook->apply_filters()
#18 /wp-includes/plugin.php(474): WP_Hook->do_action()
#19 /wp-content/plugins/woocommerce/includes/class-wc-order.php(364): do_action()
#20 /wp-content/plugins/woocommerce/includes/class-wc-order.php(222): WC_Order->status_transition()
#21 /wp-content/plugins/woocommerce/includes/class-wc-order.php(334): WC_Order->save()
#22 /wp-content/plugins/woo-rfq-for-woocommerce/includes/classes/gateway/wc-gateway-gpls-request-quote.php(117): WC_Order->update_status()
#23 /wp-content/plugins/woocommerce/includes/class-wc-checkout.php(982): WC_Gateway_GPLS_Request_Quote->process_payment()
#24 /wp-content/plugins/woocommerce/includes/class-wc-checkout.php(1206): WC_Checkout->process_order_payment()
#25 /wp-content/plugins/woocommerce/includes/class-wc-ajax.php(461): WC_Checkout->process_checkout()
#26 /wp-includes/class-wp-hook.php(307): WC_AJAX::checkout()
#27 /wp-includes/class-wp-hook.php(331): WP_Hook->apply_filters()
#28 /wp-includes/plugin.php(474): WP_Hook->do_action()
#29 /wp-content/plugins/woocommerce/includes/class-wc-ajax.php(90): do_action()
#30 /wp-includes/class-wp-hook.php(307): WC_AJAX::do_wc_ajax()
#31 /wp-includes/class-wp-hook.php(331): WP_Hook->apply_filters()
#32 /wp-includes/plugin.php(474): WP_Hook->do_action()
#33 /wp-includes/template-loader.php(13): do_action()
#34 /wp-blog-header.php(19): require_once('...')
#35 /index.php(17): require('...')
#36 {main}
  thrown in /wp-content/plugins/woo-checkout-field-editor-pro/public/class-thwcfd-public-checkout.php on line 494
[02-Jun-2022 12:18:43 UTC]