I've just realized, that there is no matter what characters are over 8 sign in my passwords.
E. g. with password: Admin1234 also will match Admin123 and Admin1235
In my Community Auth configuration I have set i authentication.php:
$config['min_chars_for_password'] = 8;
$config['max_chars_for_password'] = 256;
Is this Community Auth bug? Or something misconfigured from my side?