If a user who’s been removed from a project can still see it on their timesheet, one of two things is likely happening:
The user entered time against the project before they were removed from it
The user will be prompted to remove the time entered against that project before they will be allowed to submit the timesheet.
The user's department or ‘All Users’ is assigned to the project
If you’d like to unassign this user, but keep other users assigned to the project, you’ll need to remove the department or ‘All Users’ assignment, and assign the project to all other users one by one.
For information on assigning or removing users from projects, refer to Assigning a project team.