Exception gets thrown pasting from an RTF document (MS Word):

Exception in thread "JavaFX Application Thread" java.lang.ClassCastException: class java.lang.Object cannot be cast to class java.lang.String (java.lang.Object and java.lang.String are in module java.base of loader 'bootstrap')
at jfx.incubator.richtext/com.sun.jfx.incubator.scene.control.richtext.rtf.RTFReader$StylesheetDestination.close(RTFReader.java:785)
at jfx.incubator.richtext/com.sun.jfx.incubator.scene.control.richtext.rtf.RTFReader.endgroup(RTFReader.java:281)
at jfx.incubator.richtext/com.sun.jfx.incubator.scene.control.richtext.rtf.RTFParser.write(RTFParser.java:163)
at jfx.incubator.richtext/com.sun.jfx.incubator.scene.control.richtext.rtf.RTFReader.write(RTFReader.java:1)
at jfx.incubator.richtext/com.sun.jfx.incubator.scene.control.richtext.rtf.AbstractFilter.readFromReader(AbstractFilter.java:106)
at jfx.incubator.richtext/com.sun.jfx.incubator.scene.control.richtext.rtf.RTFReader.readFromReader(RTFReader.java:1)
at jfx.incubator.richtext/com.sun.jfx.incubator.scene.control.richtext.rtf.RTFReader.generateStyledInput(RTFReader.java:143)
at jfx.incubator.richtext/jfx.incubator.scene.control.richtext.model.RtfFormatHandler.createStyledInput(RtfFormatHandler.java:65)
at jfx.incubator.richtext/com.sun.jfx.incubator.scene.control.richtext.RichTextAreaBehavior.pasteLocal(RichTextAreaBehavior.java:1191)
at jfx.incubator.richtext/com.sun.jfx.incubator.scene.control.richtext.RichTextAreaBehavior.paste(RichTextAreaBehavior.java:1137)
at jfx.incubator.input/com.sun.jfx.incubator.scene.control.input.SkinInputMap.execute(SkinInputMap.java:187)
at jfx.incubator.input/jfx.incubator.scene.control.input.InputMap.executeDefault(InputMap.java:221)
at jfx.incubator.input/jfx.incubator.scene.control.input.InputMap.execute(InputMap.java:215)
at jfx.incubator.input/jfx.incubator.scene.control.input.InputMap.execute(InputMap.java:197)
at jfx.incubator.input/jfx.incubator.scene.control.input.InputMap.handleKeyBindingEvent(InputMap.java:187)
at jfx.incubator.input/jfx.incubator.scene.control.input.InputMap.lambda$1(InputMap.java:170)
at jfx.incubator.input/com.sun.jfx.incubator.scene.control.input.PHList.forEach(PHList.java:172)
at jfx.incubator.input/jfx.incubator.scene.control.input.InputMap.handleEvent(InputMap.java:168)
at javafx.base/com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:247)
at javafx.base/com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:232)
at javafx.base/com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:189)
at javafx.base/com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at javafx.base/com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at javafx.base/com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at javafx.base/com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.graphics/javafx.scene.Scene.processKeyEvent(Scene.java:2240)
at javafx.graphics/javafx.scene.Scene$ScenePeerListener.keyEvent(Scene.java:2770)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.get(GlassViewEventHandler.java:175)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler$KeyEventNotification.get(GlassViewEventHandler.java:1)
at javafx.graphics/com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:424)
at javafx.graphics/com.sun.javafx.tk.quantum.GlassViewEventHandler.handleKeyEvent(GlassViewEventHandler.java:203)
at javafx.graphics/com.sun.glass.ui.View.handleKeyEvent(View.java:550)
at javafx.graphics/com.sun.glass.ui.View.notifyKeyAndReturnConsumed(View.java:979)
Suppressed: java.lang.ClassCastException: class java.lang.Object cannot be cast to class java.lang.String (java.lang.Object and java.lang.String are in module java.base of loader 'bootstrap')
at jfx.incubator.richtext/com.sun.jfx.incubator.scene.control.richtext.rtf.RTFReader$StylesheetDestination.close(RTFReader.java:785)
at jfx.incubator.richtext/com.sun.jfx.incubator.scene.control.richtext.rtf.RTFReader.endgroup(RTFReader.java:281)
at jfx.incubator.richtext/com.sun.jfx.incubator.scene.control.richtext.rtf.RTFParser.close(RTFParser.java:339)
at jfx.incubator.richtext/com.sun.jfx.incubator.scene.control.richtext.rtf.RTFReader.close(RTFReader.java:319)
at jfx.incubator.richtext/jfx.incubator.scene.control.richtext.model.RtfFormatHandler.createStyledInput(RtfFormatHandler.java:66)
... 31 more