Manual enrollments and expiration time

On Moodle documentation for Manual Enrollments, one can see: Enrolment expiration action - specifies what happens when user enrolments reach expiration date. Please note that option "Unenrol user from course" purges grades, group memberships, preferences and other user related data from the courses and Default enrolment duration - this sets the default length of enrolment in new courses. From what I can understand, if I enroll a user in a course with Manual Enrollment, and if I have set the default enrolment duration to 10 minutes and the expiration action to unenrol, the user that I have enroled with this plugin will no longer belong in a course after 10 minutes (provided that the cron server has run). But, the user is not removed from the course and I have checked that the cron server is running. My moodle version is 2.4.1, and I'm wondering if I'm the only one that has noticed this and if it is working in any other version... Thanks