Cannot Remove an Admin or Billing Member from a Workspace
Error:
Organization members with Admin and Billing roles are automatically granted permissions on all Workspaces and cannot be removed from Workspaces.
What it means: The member holds an organization-level Admin or Billing role, which auto-grants access to every workspace and blocks workspace-level removal.
Solution: Change the person's organization role from Admin or Billing to User or Developer under Organization settings then Members, then remove them from the workspace.