Was wandering if the following was a bug with the unwrap function or by design?

The following example works fine. Two divs are created, one wraps the other, then unwraps, all while being disconnected, and the outcome is correct. The child div is added and has no parent as it's been unwrapped.

var l1 = $('<div style="background-color:#ff0000;height:20px;width:40px;" />');
var l2 = $('<div style="background-color:#ffff00;height:10px;width:20px;" />');
	   
l2.wrap(l1);
l2.unwrap();	
	      
if(l2.parent().length > 0){	   	   
  $('body').append(l2.parent())
}else{
  $('body').append(l2)   
}
	 

However take into consideration the following example whereby the l2 div is first added and removed from the DOM.

This time the wrap function occurs correctly but the unwrap never seems to occur. Meaning the result is the two divs are added one wrapping the other, even though unwrap has been called.

var l1 = $('<div style="background-color:#ff0000;height:20px;width:40px;" />');
var l2 = $('<div style="background-color:#ffff00;height:10px;width:20px;" />');

$('body').append(l2).contents().remove();
	   
l2.wrap(l1);
l2.unwrap();	
	      
if(l2.parent().length > 0){	   	   
  $('body').append(l2.parent())
}else{
  $('body').append(l2)   
}