Weird PHP behaviour - What's going on?

Just came across this bug recently in a PHP app. Not sure what's going on.

Basically, it shows up when using a combination of two foreach (one with &, one without).

Here's a test code that reproduce the problem:

$items = array(
 
     array('id'=>1, 'name'=>'foo', 'value'=>150),
 
     array('id'=>2, 'name'=>'bar', 'value'=>190)
 );
 
 
 foreach($items as &$item)
 {
 
     $item['percentage'] = $item['value'] * 0.75;
 
 }
 
 var_dump($items);   // All Good
 
 foreach($items as $item)
 {
 
     var_dump($item);    // Shows 1st item twice
 }
 

The second foreach loop runs the block twice, as expected, but $item remains stuck on the first item.

I understand this is likely caused by the use of the reference & in the first loop but I don't see why it should behave like this..

Any idea? is that a bug?

Getting the same result on 5.3.8, 5.3.10 & 5.4

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