Metacourse role synchronisation issue

In the site admin settings of "Course meta link", we have specified all roles with the exception of student as "Roles that are not synchronized"

We then setup Course A with students and teachers. This course is then used as a metacourse to Course B. The students get synchronized across successfully. However, the teachers also get synchronized, but have no role associated with them. I would expect that they would not get synchronized at all, rather than being synchronized with no role. This leaves the teacher with access to the course.

This person also has commented on the behaviour: http://moodle.org/mod/forum/discuss.php?d=168701

Replication steps:

1. Set site admin settings for "Course meta link" to only synchronize students
2. Set up Course A. Add a teacher and a couple of students to the course
3. Set up Course B. Add a metacourse via Settings -> Users -> Enrolment methods -> Add method 'Course meta link' and select Course A from the list
4. Check enrolled users list. The students will be synchronized and the teacher will be as well. However, the teacher will have no role.

See attachments. These were taken from demo.moodle.net.

Attachment meta_course_1 is where the three users have been enrolled. meta_course_2 shows the 2 students as enrolled but Martin is showing with no role.