On 2.6 here. I have read through the documentation on the manager role here: http://docs.moodle.org/25/en/Manager_role which addresses setting the manager role at the site and category level. I am wondering how to assign a user the role of Manager at the course level.
I assigned this role to a user, then logged in as them and they didn't have access. I thought maybe they also had to be enrolled, but that seemed to run contrary to the documentation stating this role is to give capacity for those who are not formally enrolled in the course.
I also verified that moodle/course:view is set to allow for the manager role.