Empty $_POST in controller, but not empty in yii\web\Request

I found some stranges in parsing data from a simple form. When debugging in yii\web\Request parse method (after submit form with POST method) i can see $_POST array with data, but then when I get data in Controller $_POST array became empty…How to fix it?
i already added all type of parsers, it doesn’t help.

‘request’ => [
‘csrfParam’ => ‘_csrf_test’,
‘enableCsrfValidation’ => true,
‘cookieValidationKey’ => $params[‘cookieValidationKey’],
‘parsers’ => [
‘application/json’ => \yii\web\JsonParser::class,
‘multipart/form-data’ => yii\web\MultipartFormDataParser::class,
‘application/xml’ => \yii\httpclient\XmlParser::class,

Spent whole day trying to find my post (.