Count query with group in class extends \yii\db\Query

What steps will reproduce the problem?

1. Create class QueryMyDb extends \yii\db\Query
2. Modify function in QueryModified

    public function createCommand($db = null)
    {
        if ($db === null) {
            $db = Yii::$app->get('myDb');
        }
        return parent::createCommand($db);
    }

1. Execute request

(new QueryMyDb())->from('table')
            ->groupBy('column')
            ->count();

What is the expected result?

Query to myDb

What do you get instead?

Query to db

Additional info

Problem this If use (new static()), the query will be correct