PHP Core Warning – yii\base\ErrorException

$_GET = [
    'random' => '1791268134',
];

$_COOKIE = [
    'topics-session' => '1791890161.781.16697.336698|d197bbbd1d400bd72372bc93068ad169',
    'PHPSESSID' => 'aksf7lob0ansgc6msemhb54sq7',
    '_csrf' => 'bd6b69cca49383e1eae0f8fbb4149e424baad22720cbc42093468e2b50cd40fca:2:{i:0;s:5:"_csrf";i:1;s:32:"kKh7m-3CIG91saUWw2hxav-oqBvVZt2g";}',
];

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