defining and using a custom converter for ZKBIND works but fails for "default-bind"

Array of attribute values not allowed, [self.onChange, self.onChange]
at org.zkoss.zkplus.databind.DataBinder.loadPropertyAnnotation(DataBinder.java:615)
at org.zkoss.zkplus.databind.DataBinder.addBinding(DataBinder.java:274)
at org.zkoss.zkplus.databind.AnnotateDataBinder.loadComponentPropertyAnnotationByAnnotName(AnnotateDataBinder.java:425)
at org.zkoss.zkplus.databind.AnnotateDataBinder.loadComponentPropertyAnnotation(AnnotateDataBinder.java:413)
at org.zkoss.zkplus.databind.AnnotateDataBinder.loadAnnotations(AnnotateDataBinder.java:404)
at org.zkoss.zkplus.databind.AnnotateDataBinder.loadAnnotations(AnnotateDataBinder.java:408)
at org.zkoss.zkplus.databind.AnnotateDataBinder.init(AnnotateDataBinder.java:374)
at org.zkoss.zkplus.databind.AnnotateDataBinder.<init>(AnnotateDataBinder.java:330)
at org.zkoss.zkplus.databind.AnnotateDataBinderInit.doAfterCompose(AnnotateDataBinderInit.java:154)
at org.zkoss.zk.ui.impl.Initiators$RealInits.doAfterCompose(Initiators.java:125)
at org.zkoss.zk.ui.impl.UiEngineImpl.execNewPage0(UiEngineImpl.java:409)
at org.zkoss.zk.ui.impl.UiEngineImpl.execNewPage(UiEngineImpl.java:316)
at org.zkoss.zk.ui.http.DHtmlLayoutServlet.process(DHtmlLayoutServlet.java:215)
at org.zkoss.zk.ui.http.DHtmlLayoutServlet.doGet(DHtmlLayoutServlet.java:136)

the overriding has not taken place, and 2 values are present when the binder tries to evaluate the value, it should only get the overridden value...
In ZKBIND the BinderImpl calls Annotation ann = AnnotationUtil.getOverrideAnnotation(compCtrl, attr, Binder.ZKBIND);
first to reduce duplicates, something similar has to be done for default binding in org.zkoss.zkplus.databind.DataBinder