Description:
------------
Variable is properly set but returns as NULL value

Test script:
---------------
<?php

function mtrand_except($min, $max, $except) {
    $random_number = mt_rand($min, $max);
    if(!in_array($random_number, $except)) {
        echo $random_number.'<br />';
        return $random_number;
    }
    mtrand_except($min, $max, $except);
}

$random_arr = array();
for($i=1; $i<=90; $i++) {
    $rand = mtrand_except(1, 90, $random_arr);
    echo $i.'<br />'.$rand.'<hr />';
    $random_arr[] = $rand;
}

Expected result:
----------------
60
1
60
------
19
2
19
------
57
3
57
------
etc...

Actual result:
--------------
60
1
60
------
19
2
NULL
------
57
3
57
------
etc...