Is this a bug with the iterator handling and foreach?

iterator-error.php

<?php
/**
 * In the example below, I make an iterator and assign three values to it: "foo", "bar" and "baz".
 * I then manually remove the first one (index 0) and pass the rest into foreach. I expected it
 * to just start with index 1 and go on and loop through the rest but there's no output at all.
 *
 * Is this a bug?
 */

class Items implements \Iterator
{
    private $items = [];
    private $index = 0;

    public function current()
    {
        return $this->items[$this->index];
    }
    public function next()
    {
        $this->index++;
    }
    public function valid()
    {
        return isset($this->items[$this->index]);
    }
    public function key()
    {
        return $this->index;
    }
    public function rewind()
    {
        $this->index = 0;
    }

    public function add($item)
    {
        $this->items[] = $item;
    }
    public function remove($index)
    {
        unset($this->items[$index]);
    }
}
//-------------------
$items = new Items();

$items->add('foo');
$items->add('bar');
$items->add('baz');

$items->remove(0);

// Expected that the loop would start with the first index of "1"
// but it doesn't output anything
foreach($items as $item) {
    echo $item."\n";
}

@enygma how about changing the unset($this->items[$index]); to array_splice($this->items, $index, 1);? This will reset the indices.