Hi, same problem here:
I'm working on a script that check unenrollmcnts form an external list of users and unenroll a single user deleting a specific role.
When I pass the specific role that must be unenrolled the web service simply deletes all the enrollment. Note that if a student has multiple roles It must stay enrolled with the other roles except the one the script has removed.
It seems the method ignores the roleid