I'm trying to remove admin access to a user in a project from the Manage Project / Access project list. The documentation says I might need to restart the instance, which I did by using the Restart Server command in the Admin menu and I also restarted the vm Matillion runs on.
The Admin check box always comes back for that user.
I had a similar issue where I would uncheck a user's Admin access, click "OK" but when I went back to the Manage Project menu, the change wasn't reflected.
After a bit of digging around I released I had to first uncheck the Public Users checkbox and was then able to remove admin privileges as well as access to the project.