Using "-fx-border-image-repeat: repeat" with "-fx-border-image-slice: 100% fill;" produces a chain of exceptions (slice percent is not important and can be changed):

java.lang.IllegalArgumentException: Subimage dimensions must be > 0
at com.sun.prism.Image.createSubImage(Image.java:381)
at com.sun.prism.Image.createSubImage(Image.java:381)
at com.sun.javafx.sg.prism.NGRegion.paintTiles(NGRegion.java:1665)
at com.sun.javafx.sg.prism.NGRegion.paintTiles(NGRegion.java:1613)
at com.sun.javafx.sg.prism.NGRegion.renderContent(NGRegion.java:1238)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:1598)
at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1520)
at com.sun.javafx.sg.prism.NGGroup.renderChildren(NGGroup.java:233)
at com.sun.javafx.sg.prism.NGGroup.renderContent(NGGroup.java:199)
at com.sun.javafx.sg.prism.NGNode.doRender(NGNode.java:1598)
at com.sun.javafx.sg.prism.NGNode.render(NGNode.java:1520)
at com.sun.javafx.tk.quantum.ViewPainter.doPaint(ViewPainter.java:99)
at com.sun.javafx.tk.quantum.AbstractPainter.paintImpl(AbstractPainter.java:210)
at com.sun.javafx.tk.quantum.PresentingPainter.run(PresentingPainter.java:95)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:508)
at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
at com.sun.javafx.tk.RenderJob.run(RenderJob.java:58)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at com.sun.javafx.tk.quantum.QuantumRenderer$PipelineRunnable.run(QuantumRenderer.java:129)
at java.lang.Thread.run(Thread.java:724)
D3D Vram Pool: 269 840 used (0,1%), 269 840 managed (0,1%), 268 435 456 total
6 total resources being managed
2 permanent resources (33.3%)
1 resources locked (16.7%)
4 resources contain interesting data (66.7%)
0 resources disappeared (0.0%)

Other repeat styles ("stretch", "round" etc) do not produce exceptions.