Why is the last array returning null?

For some reason that last array is returning NULL. It's supposed to be returning "H11":

<?php
$all_description_blb = array();
$all_etymologyStrongs = array();

$string1 = "";
$string2 = "";
$string3 = "";
$string4 […]

See original post by invalid@example.com (gilgalbiblewheel)