Issue with Session

There's no global object in CI4 like there was in CI3. So if you need to access the session in your model, you need to call the session service again. You can also use the session() helper to minimize the amount of code:

PHP Code:

$this->session = session(); 


See https://codeigniter.com/user_guide/libra...-a-session for more details.

For your second question, I don't know why you always get true. All this function do is: 

PHP Code:

return isset($_SESSION[$key]); 


Source: https://github.com/codeigniter4/CodeIgni...n.php#L503