title: RegEx failing since PHP 7.4, working in 7.3
body: <p>Any ideas why this preg_match works up to PHP7.2 but fails with 7.3+ ?</p>
  <pre><code>$word = 'umweltfreundilch'; //real life example :/
  preg_match('/^(?U)(.*(?:[aeiouyäöü])(?:[^aeiouyäöü]))(?X)(.*)$/u', $word, $matches);
  var_dump($matches);
  </code></pre>
  <blockquote>
  <p>Warning: preg_match(): Compilation failed: unrecognized character after (? or (?-</p>
  </blockquote>
  <p>PHP 7.2 and below output:</p>
  <pre><code>array(3) {
    [0]=&gt;
    string(16) &quot;umweltfreundilch&quot;
    [1]=&gt;
    string(2) &quot;um&quot;
    [2]=&gt;
    string(14) &quot;weltfreundilch&quot;
  }
  </code></pre>
  <p>RegEx seems to be ok, doesn't it?<br />
  <a href="https://regex101.com/r/LGdhaM/1" rel="noreferrer">https://regex101.com/r/LGdhaM/1</a></p>