MacOS/Prism: IllegalArgumentException in com.sun.prism.impl.BaseTexture wedges the whole UI.

In the authoring tool we're using:
             
            final Object platformImage = scene.renderToImage(null);
            image = Image.impl_fromPlatformImage(platformImage);

to create an image of an object (such as a Rectangle, or a Group, or whatever) in order to
display a thumbnail image of it in the inspector.

This works well on windows, but on MacOS we get an IllegalArgumentException in the render thread
which wedges the whole UI:

java.lang.IllegalArgumentException: Upload requires 2704 elements, but only 0 elements remain in the buffer
        at com.sun.prism.impl.BaseTexture.checkUpdateParams(BaseTexture.java:162)
        at com.sun.prism.es2.ES2Texture.update(ES2Texture.java:409)
        at com.sun.prism.impl.BaseTexture.update(BaseTexture.java:104)
        at com.sun.prism.impl.BaseResourceFactory.createTexture(BaseResourceFactory.java:113)
        at com.sun.prism.impl.BaseResourceFactory.getCachedTexture(BaseResourceFactory.java:93)
        at com.sun.prism.impl.BaseResourceFactory.getCachedTexture(BaseResourceFactory.java:84)
        at com.sun.javafx.sg.prism.NGImageView.renderContent(NGImageView.java:311)
        at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:95)
        at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:36)
        at com.sun.javafx.sg.BaseNode.render(BaseNode.java:909)
        at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:148)
        at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:95)
        at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:36)
        at com.sun.javafx.sg.BaseNode.render(BaseNode.java:909)
        at com.sun.javafx.tk.quantum.PrismPen$PaintRunnable.paintImpl(PrismPen.java:196)
        at com.sun.javafx.tk.quantum.PrismPen$PaintRunnable.run(PrismPen.java:310)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
        at java.util.concurrent.FutureTask$Sync.innerRunAndReset(FutureTask.java:317)
        at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:150)
        at com.sun.prism.tkal.RenderJob.run(RenderJob.java:29)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
        at java.lang.Thread.run(Thread.java:680)


The small example attached (needs jfxrt.jar and AuthoringTool.jar) shows that.
It creates a Rectangle in a Scene, then call the NodeRender (a class we use in the AT) to
create an image from it, then adds the image to the scenegraph.
shortly after the exception is raised.