Modification of array iterated through foreach by reference may cause undefined iteration behavior

Description

The following code:

<?php

function demo($array) {
	$debug_backtrace = [];

	foreach ($array as $key => &$value) {
		echo "{$value}\r\n";

		if ($value == 3) {
			unset($array[$key]);

			continue;
		}

		$debug_backtrace[] = debug_backtrace();
	}
}

demo([1, 2, 3]);

Resulted in this output:

1
2
3
1
2

But I expected this output instead:

1
2
3

Please pay attention to usage of the ampersand for the $value.
Please note that commenting out the "$debug_backtrace[] = debug_backtrace();" will resolve the issue.

This happens for PHP 8.0.15 as well.

PHP Version

PHP 8.1.2

Operating System

Windows 11 & Ubuntu 20.04

Start by running the supplied PHP snippet on PHP 8.1.2, then review the PHP documentation covering foreach by reference, unset, and debug_backtrace. Done means the relevant documentation clearly explains the observed iteration behavior and expected result.