Getting PHP errors “get_cart_contents() on null” in admin

If I have both Polylang and WooCommerce Checkout Manager (and WooCommerce, no other plugins) installed, I get four PHP error messages in the error log every time I open the product list in Admin (and on some other pages as well, e.g. Product editing page) like this one:

PHP Fatal error:  Uncaught Error: Call to a member function get_cart_contents() on null in /home/shoppingt/wp-content/plugins/woocommerce-checkout-manager/lib/view/frontend/class-fields-disable.php:157
Stack trace:
#0 /home/shoppingt/wp-includes/class-wp-hook.php(310): QuadLayers\WOOCCM\View\Frontend\Fields_Disable->disable_by_product()
#1 /home/shoppingt/wp-includes/plugin.php(205): WP_Hook->apply_filters()
#2 /home/shoppingt/wp-content/plugins/woocommerce-checkout-manager/lib/model/class-field.php(285): apply_filters()
#3 /home/shoppingt/wp-content/plugins/woocommerce-checkout-manager/lib/view/frontend/class-fields-i18n.php(24): QuadLayers\WOOCCM\Model\Field->get_fields()
#4 /home/shoppingt/wp-includes/class-wp-hook.php(308): QuadLayers\WOOCCM\View\Frontend\Fields_I18n->init_polylang()
#5 /home/shoppingt/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters()
#6 /home/shoppingt/wp-includes/plugin.php(517): WP_Hook->do_action()
#7 /home/shoppingt/wp-settings.php(617): do_action()
#8 /home/shoppingt/wp-config.php(112): require_once('/home/shoppingt...')
#9 /home/shoppingt/wp-load.php(50): require_once('/home/shoppingt...')
#10 /home/shoppingt/wp-blog-header.php(13): require_once('/home/shoppingt...')
#11 /home/shoppingt/index.php(17): require('/home/shoppingt...')
#12 {main}
  thrown in /home/shoppingt/wp-content/plugins/woocommerce-checkout-manager/lib/view/frontend/class-fields-disable.php on line 157

The product list page itself opens all right. The 500 responses go to AJAX requests like these:

/wp-json/wc-admin/onboarding/tasks?_locale=user
/wp-json/wc-admin/options?options=woocommerce_ces_tracks_queue&_locale=user
/wp-json/wc-analytics/admin/notes?page=1&per_page=25&type=error%2Cupdate&status=unactioned&_locale=user
/wp-json/wc-admin/options?options=woocommerce_allow_tracking&_locale=user

Tested with WooCommerce Checkout Manager 7.0.3, WooCommerce 7.4.0, Polylang 3.3.1.

The errors disappear if I disable either WooCommerce Checkout Manager or Polylang.