AJAX and pure JS API token request break user session

API token request break user session if logged in, but request successful.
The result is the same for $.ajax and pure JS fetch
Tested on two projects

    let url = '<?php echo $this->getUrl('rest/V1/integration/customer/token') ?>'; 
    let requestData = {
        'username': 'sfgzsdfg@gmail.com',
        'password': 'zdgszg'
    }
    let header = {
        'Content-Type': 'application/json'
    }

    $.ajax({
        url: url,
        type: 'POST',
        headers: header,
        data: JSON.stringify(requestData),
        success: function (data) {
            console.log('Data:', data)
        },
        error: function (e) {
            console.log(e);
        }
    });

Need token to get cart data, etc