javascript error when use include with auto mode

<zk>
	<label multiline="true">
		1.click on button 1, you will see window1's title was changed to current time without error
		2.click on button 2, you will see window2's title was changed to current time without error
		3.click on button 3, you will see window3's title was changed to current time without error
		this bug shows a error when click on button 3, and if you check au response, you will see weird data (duplicated data) 
	</label>
	<window>
		<zscript>
			int count = 0;
		</zscript>
		
		<include id="inc1" src="bug2.zul" mode="defer" />
		<include id="inc2" src="bug2.zul" mode="instant" />
		<include id="inc3" src="bug2.zul" mode="auto" />
		
		
		<button label="reload 1" onClick='inc1.src = "bug2.zul?ts="+count++'/>
		<button label="reload 2" onClick='inc2.src = "bug2.zul?ts="+count++'/>
		<button label="reload 3" onClick='inc3.src = "bug2.zul?ts="+count++'/>
	</window>
</zk>

<window>
	<zscript>
	java.util.Date time = new java.util.Date();
	</zscript>
	<window id="win" title="Hello World!! ${time}" border="normal" width="500px">
		<button label="detach" onClick='win.detach()' />
	</window>
</window>