@DilipBarman This is quite interesting… and he just started being able to see the course as an instructor? Is he able to actually publish and unpublish content, or just view that content? And, you are able to see users in all sections of your course, right? Sometimes it’s set to limit you to only see certain students in a section, and if there’s an additional section you’re not enrolled in inside that course (that a canvas admin could make), they can make it so you are unable to see them listed as a teacher or TA.
Have you by chance removed him and re-added him to the course? I recommend removing him, seeing if he is still able to access the course with the teacher view, and then re add him. If he can still see the course as a teacher even when he isn’t enrolled, then he’s either enrolled in a section as a teacher in the course that an admin made that you for some reason don’t see, was previously enrolled as a teacher or TA accidentally recently and the admin only concluded the enrollment and didn’t actually delete it, or he is an admin of the account your course is associated with.
I also recommend reaching out to your school’s canvas team to see if they can see what’s going on. They’re able to pull up all of his information on the admin side and see all the courses, groups and accounts that he is enrolled in, as well as with what role.
All the best!
Noah