FULL PRODUCT VERSION :
Java 8.0_131

ADDITIONAL OS VERSION INFORMATION :
macOS Sierra Version 10.12.6

EXTRA RELEVANT SYSTEM CONFIGURATION :
This issue has also been reported (not by me) in StackOverflow here:
https://stackoverflow.com/questions/29134625/javafx-treetableview-exception-when-sorting-with-multiple-rows-selected

A DESCRIPTION OF THE PROBLEM :
In a TreeTableView with selectionMode set to multiple, if you multi select some cells and then reorder, you will get an IndexOutOfBoundsException.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run the sample code, expand the root node and multi select some cells. Then re-order the column.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Column should reorder without an IndexOutOfBoundsException.
ACTUAL -
App crashes with an IndexOutOfBoundsException

ERROR MESSAGES/STACK TRACES THAT OCCUR :
Exception in thread "JavaFX Application Thread" java.lang.IndexOutOfBoundsException
at com.sun.javafx.scene.control.ReadOnlyUnbackedObservableList.subList(ReadOnlyUnbackedObservableList.java:136)
at javafx.collections.ListChangeListener$Change.getAddedSubList(ListChangeListener.java:242)
at javafx.scene.control.TreeTableView$TreeTableViewArrayListSelectionModel.handleSelectedCellsListChangeEvent(TreeTableView.java:3244)
at javafx.scene.control.TreeTableView$TreeTableViewArrayListSelectionModel.access$2000(TreeTableView.java:2289)
at javafx.scene.control.TreeTableView.sort(TreeTableView.java:1817)
at javafx.scene.control.TreeTableView.doSort(TreeTableView.java:1855)
at javafx.scene.control.TreeTableView.lambda$new$114(TreeTableView.java:383)
at com.sun.javafx.collections.ListListenerHelper$Generic.fireValueChangedEvent(ListListenerHelper.java:329)
at com.sun.javafx.collections.ListListenerHelper.fireValueChangedEvent(ListListenerHelper.java:73)
at javafx.collections.ObservableListBase.fireChange(ObservableListBase.java:233)
at javafx.collections.ListChangeBuilder.commit(ListChangeBuilder.java:482)
at javafx.collections.ListChangeBuilder.endChange(ListChangeBuilder.java:541)
at javafx.collections.ObservableListBase.endChange(ObservableListBase.java:205)
at javafx.collections.ModifiableObservableListBase.setAll(ModifiableObservableListBase.java:90)
at javafx.collections.ObservableListBase.setAll(ObservableListBase.java:250)
at com.sun.javafx.scene.control.skin.TableColumnHeader.sortColumn(TableColumnHeader.java:795)
at com.sun.javafx.scene.control.skin.TableColumnHeader.lambda$static$55(TableColumnHeader.java:243)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3757)
at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3485)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1762)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2494)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:381)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$354(GlassViewEventHandler.java:417)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:416)
at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
at com.sun.glass.ui.View.notifyMouse(View.java:937)

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import javafx.application.Application;
import javafx.beans.property.SimpleStringProperty;
import javafx.scene.Scene;
import javafx.scene.control.SelectionMode;
import javafx.scene.control.TreeItem;
import javafx.scene.control.TreeTableColumn;
import javafx.scene.control.TreeTableView;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;


public class TreeViewSample extends Application {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        launch(args);
    }
    
    @Override
    public void start(Stage primaryStage) {
        
        TreeItem<String> treeItemRoot = new TreeItem<> ("Root");
        
        TreeItem<String> nodeItemA = new TreeItem<>("Item A");
        TreeItem<String> nodeItemB = new TreeItem<>("Item B");
        TreeItem<String> nodeItemC = new TreeItem<>("Item C");
        treeItemRoot.getChildren().addAll(nodeItemA, nodeItemB, nodeItemC);
        
        
        TreeTableView<String> treeView = new TreeTableView<>(treeItemRoot);
        treeView.getSelectionModel().setSelectionMode(SelectionMode.MULTIPLE);
        StackPane root = new StackPane();
        root.getChildren().add(treeView);
        
        
        TreeTableColumn<String, String> column = new TreeTableColumn<>();
        column.setCellValueFactory(value ->
        {
            return new SimpleStringProperty(value.getValue().getValue());
        });
        column.setPrefWidth(100);
        
        treeView.getColumns().add(column);
        
        Scene scene = new Scene(root, 300, 250);
        
        primaryStage.setTitle("java-buddy.blogspot.com");
        primaryStage.setScene(scene);
        primaryStage.show();
    }
}
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Have to clear the selection before sorting.