We have
fixed this issue in magento core file.
lib/Varien/Data/Collection.php
public function
addItem(Varien_Object $item)
{
$itemId = $this->_getItemId($item);
if
(!is_null($itemId)) {
if
(isset($this->_items[$itemId])) {
//
throw new Exception('Item ('.get_class($item).') with the same id
"'.$item->getId().'" already exist');
}
else {
$this->_items[$itemId]
= $item;
}
}
else
{
$this->_items[]
= $item;
}
return
$this;
}
