A user becomes a member of a project's team, if the user is granted a role marked as "team role" in this project. Thus, to delete a user from a project's team, essentially you need to revoke any team role from the user in this project.
To delete a user from the Team:
- Delete the user from the <project_name>-team user group.
- If the user is still displayed in the Team list, check the own roles granted directly to this user and remove the team roles affecting this project.
- Check user's group membership and remove him/her from the groups that have a team role in this project.
- When done, check if user was added to the list of Assignees, and, if necessary, delete him/her from the project Assignees.