In 3.11 a site-admin user who gets enrolled to a course as a "Teacher" does not have a "Add submission" button when visiting assignment.

In 4.0+ a site-admin user who gets enrolled to a course as a "Teacher" has the "Add submission" button when visiting an assignment. This is despite the mod/assign:submit is Not Set for teacher role.

Take note that in 4.0+ a user (NOT a site-admin) who gets enrolled to a course as a "Teacher" does NOT have the "Add submission".

So this appears to affect only 4.0 up to 4.2+ and users who are site-admin.

Replication: 4.0 to 4.2

1. Add a user to site-admin.
2. Create a course and enrol that user as a Teacher
3. As the site-admin user (who is enrolled as a teacher), visit the course and assignment
4. RESULT: The "Add submission" button is available.
5. Add a user (NOT a site-admin) and enrol that user as a "Teacher" to that course.
6. Visit the assignment
7. RESULT: There is NO "Add submission".