Hotspot Not Visible - ?

This is my problem:

I'm trying to create a loop between two graphics. You click the first image, it becomes invisible and makes the second visible. You click the second image, and it becomes invisible and makes the first visible again. This works great on desktop, but on tablets, the second image does not become visible. It is, however, still clickable, and any other functions assigned to it still work.

I have tested on iPad 1, iPad 2, and Galaxy Tab 2 - the problem is consistent.

What is causing this issue on iPad and other tablets?

<hotspot name="target"
			 url="images/target_icon.png"
			 devices="desktop|html5|ipad|retina+ipad|all"
			 ath="-9.0" atv="-37.0"
			 edge="center"
			 onover="set(alpha,1);set(effect,glow(0xFFF8C6,.5,25,5))"
 			 onout="set(alpha,.8);set(alpha,8);set(effect,glow(0xFFF8C6,.0,0,0))"
			 onclick="set(visible,false); set(hotspot[box].visible,true)"
			 />
			 
	        <hotspot name="box"
			 url="images/box.png"
			 devices="desktop|html5|ipad|mobile"
			 visible="false"
			 ath="-9.0" atv="-37.0"
			 edge="center"
			 onclick="set(visible,false); set(hotspot[target].visible,true)"
			 />

Note: This problem only happens if the second hotspot image starts out as visible="false"
If visible="true", the problem does not occur, everything works as it should.

Any suggestions?

Thanks