MacGestureSupport.notifyNextTouchEvent IllegalStateException not on JavaFX Application Thread on exit

I sometimes get exceptions thrown when closing a Java application on a Mac.

I use the touchpad on the MacBook Air for all interaction.

To generate exceptions:
  1. Run any windowed JavaFX Application.
  2. Click on the red close window circle icon in the window frame.
The application will shutdown.

Two times out of ten, on shutdown I see the following exception printed to the console:

Exception in thread "JavaFX Application Thread" java.lang.IllegalStateException: This operation is permitted on the event thread only; currentThread = JavaFX Application Thread
at com.sun.glass.ui.Application.checkEventThread(Application.java:427)
at com.sun.glass.ui.View.isClosed(View.java:409)
at com.sun.glass.ui.mac.MacTouchInputSupport.notifyNextTouchEvent(MacTouchInputSupport.java:122)
at com.sun.glass.ui.mac.MacGestureSupport.notifyNextTouchEvent(MacGestureSupport.java:77)