Hi Scott,
Thank You for example. I defined XML View id of SubView with wrong definition like
<mvc:XMLView id="" viewName=""></mvc:XMLView>
instead of
<mvc:View id="idSub1" class="viewPadding" controllerName="zxmlembed.view.Sub1"
displayBlock="true" xmlns="sap.m" xmlns:c="sap.ui.commons" xmlns:mvc="sap.ui.core.mvc" >
<Label text="Test" />
</mvc:View>
Note : From Debugging , I found stack flow error from which I didn't get enough clues.