Session loaded multiple times

Hi,
i am using codeigniter 3.xx. I got the following error on every pageview:
DEBUG - 2020-02-11 14:36:39 --> Session class already loaded. Second attempt ignored

The session is loaded with in the autoload config and i can not find the
$this->load->library('session'); anywhere in the code so i think it should not load twice.

can someone tell me how to fix this?

thanks and best regards,
Alex