The preg_replace function of PHP 8.1 shows a strange behavior when combined with double lower quotation marks.

Here is a short example, that shows the issue:

<?php 
        #this does not work
    $bearbeitet = "Hallo „Pivot text";
    $bearbeitet = preg_replace("/[W][Pp][Ii][Vv][Oo][Tt][W]/", " <span class='abbrv' title='Performance Programm'>PIVOT</span> ", $bearbeitet);
    echo $bearbeitet;
?>

If you run this code it will put a strange symbol infront of the replaced text that breaks my skript. If you have any other symbol instead of the double lower quotation marks it works fine:

<?php 
    #this works
    $bearbeitet = "Hallo (Pivot text";
    $bearbeitet = preg_replace("/[W][Pp][Ii][Vv][Oo][Tt][W]/", " <span class='abbrv' title='Performance Programm'>PIVOT</span> ", $bearbeitet);
    echo $bearbeitet;
?>

Am I missing something or is that a Bug in PHP?