FOX - Currency Switcher Professional for WooCommerce

Plugin: https://yithemes.com/themes/plugins/yith-woocommerce-color-and-label-variations/

• In file wp-content\plugins\yith-woocommerce-color-label-variations-premium\includes\class.yith-wccl-frontend.php add next code

  if (class_exists('WOOCS')) {
      global $WOOCS;
      $curr_curr = $WOOCS->current_currency;
      $transient = 'yith_wccl_get_available_variations_' . $curr_curr . '_' . $product_id;
  }