At the moment, we're using a different system to enrol new users via the manual enrolment method.
This creates a problem. The enrol log entry will only be created if someone is manually managing the enrolments for a course.
Please move the add_to_log from /enrol/manual/manage.php to /lib/enrollib.php in class enrol_plugin function enrol_user.
This might also be valid for unenrolments.
The effect this will have is people using automated systems to enrol users, will actually have logs .