Have you tried to use selenium on it as well?
import org.openqa.selenium.By as By
import org.openqa.selenium.support.ui.Select as Select
import org.openqa.selenium.WebDriver as WebDriver
import com.kms.katalon.core.webui.driver.DriverFactory as DriverFactory
Select select = new Select(DriverFactory.getWebDriver().findElement(By.xpath("your elements pathway")))
String optionText = select.getFirstSelectedOption().getText()