FULL PRODUCT VERSION :
java version "1.8.0_73"
Java(TM) SE Runtime Environment (build 1.8.0_73-b02)
Java HotSpot(TM) 64-Bit Server VM (build 25.73-b02, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Version 6.1.7601

A DESCRIPTION OF THE PROBLEM :
We discovered the bug when trying to add subcolumns dynamically via a changelistener. We rebuild the bug with the code below (adding it with an actionevent).

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Add subcolumns dynamically on ActionEvent or binding

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Subcolumns will be added
ACTUAL -
Columns are added (see cells) but without a header

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
See testing code below:

import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.layout.Priority;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;


public class MainNestedCols extends Application{

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

    @Override
    public void start(Stage stage) {
        Parent root = createRoot();
        Scene scene = new Scene(root);
        stage.setScene(scene);
        stage.setTitle("Bug Table Nested Columns Test");
        stage.show();
    }

    private Parent createRoot() {
        ObservableList<String> values = FXCollections.observableArrayList();
        values.addAll("Alice", "Bob");

        TableView<String> tableView = new TableView<>(values);

        TableColumn<String, String> column = new TableColumn<>("Col");
        column.setMinWidth(100);
        tableView.getColumns().add(column);

        Button button = new Button("Add");
        button.setOnAction(e -> {

            TableColumn<String, String> nestedCol = new TableColumn<>("Subcol1");
            column.getColumns().add(nestedCol);
        });

        VBox vBox = new VBox();
        vBox.getChildren().addAll(tableView, button);
        VBox.setVgrow(tableView, Priority.ALWAYS);
        return vBox;
    }
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Bug does not occurr, when there is already atleast 1 subcolumn