PHP Core Warning – yii\base\ErrorException

$_GET = [
    'random' => '1791438418',
];

$_COOKIE = [
    'topics-session' => '1791616026.279.17008.774328|d197bbbd1d400bd72372bc93068ad169',
    'PHPSESSID' => 'nkidd1021fhchdt849e5qs5uo7',
    '_csrf' => '34a7904c85cda60f0227c4a38400fb1105ab27b494601effccd39ded2c1f442ca:2:{i:0;s:5:"_csrf";i:1;s:32:"SMhUWcOeGIYPh7g2_0yiww85kM8IGCLz";}',
];

$_SESSION = [
    '__flash' => [],
];