nartcan

I just found the cause:
https://www.ads-software.com/plugins/woo-order-splitter/

After disabling this plugin, it’s resolved.

Also, using Query Monitor plugin, I’ve observed these PHP errors:

wp-content/plugins/woocommerce/templates/checkout/form-shipping.php:62
wc_get_template()
wp-content/plugins/woocommerce/includes/class-wc-checkout.php:303
WC_Checkout->checkout_form_shipping()
wp-includes/class-wp-hook.php:307
do_action('woocommerce_checkout_shipping')
wp-content/plugins/woocommerce/templates/checkout/form-checkout.php:44
wc_get_template()
wp-content/plugins/woocommerce/includes/shortcodes/class-wc-shortcode-checkout.php:293
WC_Shortcode_Checkout::checkout()
wp-content/plugins/woocommerce/includes/shortcodes/class-wc-shortcode-checkout.php:67
WC_Shortcode_Checkout::output()
wp-content/plugins/woocommerce/includes/class-wc-shortcodes.php:72
WC_Shortcodes::shortcode_wrapper()
wp-content/plugins/woocommerce/includes/class-wc-shortcodes.php:95
WC_Shortcodes::checkout()
wp-includes/shortcodes.php:356
do_shortcode_tag()
Unknown location
preg_replace_callback()
wp-includes/shortcodes.php:228
do_shortcode()
wp-includes/class-wp-hook.php:307
apply_filters('the_content')
wp-includes/post-template.php:253
the_content()
wp-content/themes/oceanwp/partials/page/article.php:20
load_template('wp-content/themes/oceanwp/partials/page/article.php')
wp-includes/template.php:716
locate_template()
wp-includes/general-template.php:204
get_template_part('partials/page/article')
wp-content/themes/oceanwp/partials/page/layout.php:20
load_template('wp-content/themes/oceanwp/partials/page/layout.php')
wp-includes/template.php:716
locate_template()
wp-includes/general-template.php:204
get_template_part('partials/page/layout')
wp-content/themes/oceanwp/page.php:36