FXMLLoader fails to load attribute styleClass on Spinner

When loading a Spinner from an FXML, FXMLLoader ignored attribute styleClass.

Take the following FXML:

<?xml version="1.0" encoding="UTF-8"?>

<?import java.lang.*?>
<?import java.util.*?>
<?import javafx.scene.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>

<VBox id="AnchorPane" style="-fx-spacing: 6;" prefHeight="400.0" prefWidth="600.0" xmlns:fx="http://javafx.com/fxml/1" fx:controller="test.TestFXMLController">
    <Button fx:id="button" styleClass="my-button"/>
    <ComboBox fx:id="combo" styleClass="my-combo"/>
    <Spinner fx:id="spinner" styleClass="my-spinner"/>
</VBox>

And the following controller:

package test;

import java.net.URL;
import java.util.ResourceBundle;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Button;
import javafx.scene.control.ComboBox;
import javafx.scene.control.Spinner;

public class TestFXMLController implements Initializable {
    @FXML
    private Button button;
    @FXML
    private ComboBox combo;
    @FXML
    private Spinner spinner;

    @Override
    public void initialize(URL location, ResourceBundle resources) {
        System.out.println("> Button");
        button.getStyleClass().forEach(System.out::println);
        System.out.println("> ComboBox");
        combo.getStyleClass().forEach(System.out::println);
        System.out.println("> Spinner");
        spinner.getStyleClass().forEach(System.out::println);
    }
}

And the following app class:
package test;

import java.io.IOException;
import java.net.URL;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;

public class Main extends Application {
    
    @Override
    public void start(Stage primaryStage) throws IOException {
        final URL fxmlURL = getClass().getResource("test.fxml");
        final FXMLLoader fxmlLoader = new FXMLLoader(fxmlURL);
        final Parent root = fxmlLoader.load();
        Scene scene = new Scene(root);
        primaryStage.setTitle("test");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }
}

The output of this app is:

> Button
button
my-button
> ComboBox
combo-box-base
combo-box
my-combo
> Spinner
spinner

The Spinner object created by the FXMLLoader is missing the style "my-spinner"