title: Laravel - Malformed UTF-8 characters, possibly incorrectly encoded
body: <p>That error occurs in my Laravel application in some Ajax requests, when the page is reloaded. Some requests fail and return the following response:</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>exception: "InvalidArgumentException"
  file: "C:\wamp64\www\&lt;my app directory&gt;\vendor\laravel\framework\src\Illuminate\Http\JsonResponse.php"
  line: 75
  message: "Malformed UTF-8 characters, possibly incorrectly encoded"</code></pre>
  </div>
  </div>
  </p>
  
  <p>What causes that error? How to fix it?</p>