Exception:
java.lang.RuntimeException: A bound value cannot be set.
at javafx.beans.property.DoublePropertyBase.set(DoublePropertyBase.java:118)
at javafx.beans.property.DoubleProperty.setValue(DoubleProperty.java:39)
at javafx.scene.control.TextArea.setScrollTop(TextArea.java:549)
at com.sun.javafx.scene.control.skin.TextAreaSkin$5.changed(TextAreaSkin.java:365)
at com.sun.javafx.scene.control.skin.TextAreaSkin$5.changed(TextAreaSkin.java:362)
at com.sun.javafx.binding.ExpressionHelper$MultipleChange.fireValueChangedEvent(ExpressionHelper.java:382)
at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:64)
at javafx.beans.property.DoublePropertyBase.fireValueChangedEvent(DoublePropertyBase.java:82)
at javafx.beans.property.DoublePropertyBase.markInvalid(DoublePropertyBase.java:89)
at javafx.beans.property.DoublePropertyBase.set(DoublePropertyBase.java:122)
at javafx.scene.control.ScrollPane.setVvalue(ScrollPane.java:239)
at com.sun.javafx.scene.control.skin.TextAreaSkin$12.changed(TextAreaSkin.java:434)
at com.sun.javafx.scene.control.skin.TextAreaSkin$12.changed(TextAreaSkin.java:429)
at com.sun.javafx.binding.ExpressionHelper$SingleChange.fireValueChangedEvent(ExpressionHelper.java:181)
at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:64)
at javafx.beans.property.DoublePropertyBase.fireValueChangedEvent(DoublePropertyBase.java:82)
at javafx.beans.property.DoublePropertyBase.markInvalid(DoublePropertyBase.java:89)
at javafx.beans.property.DoublePropertyBase.bind(DoublePropertyBase.java:162)
at javafx_textarea_scrolltopleft.JavaFX_TextArea_ScrollTopLeft$1.handle(JavaFX_TextArea_ScrollTopLeft.java:41)
at javafx_textarea_scrolltopleft.JavaFX_TextArea_ScrollTopLeft$1.handle(JavaFX_TextArea_ScrollTopLeft.java:38)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:69)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:162)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:115)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:38)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:37)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:53)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:28)
at javafx.event.Event.fireEvent(Event.java:171)
at javafx.scene.Node.fireEvent(Node.java:6035)
at javafx.scene.control.Button.fire(Button.java:179)
at com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:189)
at com.sun.javafx.scene.control.skin.SkinBase$4.handle(SkinBase.java:326)
at com.sun.javafx.scene.control.skin.SkinBase$4.handle(SkinBase.java:319)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:64)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:162)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:115)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:38)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:37)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:53)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:33)
at javafx.event.Event.fireEvent(Event.java:171)
at javafx.scene.Scene$MouseHandler.process(Scene.java:2893)
at javafx.scene.Scene$MouseHandler.process(Scene.java:2687)
at javafx.scene.Scene$MouseHandler.access$1300(Scene.java:2653)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1279)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:1911)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:204)
at com.sun.glass.ui.View.handleMouseEvent(View.java:326)
at com.sun.glass.ui.View.notifyMouse(View.java:674)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.access$100(WinApplication.java:29)
at com.sun.glass.ui.win.WinApplication$2$1.run(WinApplication.java:62)
at java.lang.Thread.run(Thread.java:722)

Code:
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Slider;
import javafx.scene.control.SliderBuilder;
import javafx.scene.control.TextArea;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

/**
 * @author alexandr_kirov
 */
public class JavaFX_TextArea_ScrollTopLeft extends Application {


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

    @Override
    public void start(Stage stage) throws Exception {
        final TextArea ta = new TextArea();
        for (int i = 0; i < 1000; i++) {
            ta.setText(ta.getText() + " some text");
            if (i % 10 == 0)
                ta.setText(ta.getText() + "\n");
        }
        
        Button setBindButton = new Button("Set bind button");
        
        final Slider s1 = SliderBuilder.create().max(200).min(0).value(10).showTickLabels(true).showTickMarks(true).build();
        final Slider s2 = SliderBuilder.create().max(200).min(0).value(10).showTickLabels(true).showTickMarks(true).build();
        
        setBindButton.setOnAction(new EventHandler<ActionEvent>(){
            @Override
            public void handle(ActionEvent t) {
                ta.scrollTopProperty().bind(s1.valueProperty());
                ta.scrollLeftProperty().bind(s2.valueProperty());
            }
        });
        
        VBox vb = new VBox(5);
        vb.getChildren().addAll(ta, setBindButton, s1, s2);
        Scene scene = new Scene(vb, 300, 300);
        stage.setScene(scene);
        stage.show();
    }
}

Steps to reproduce:
Click on button "Set bind button".