Not able to remove privilege from a custom job role created as part of migration in security console

Summary:

We have a custom job role for procurement which is created in production as part of migration and not in security console. Recently we have been trying to remove a privilege 'Manage Change Order' from this custom role, in the function security privilege screen this privilege shows as not being inherited from any other role. On deleting and saving the role it shows that the record is saved, however on checking the role again the privilege still shows in the role. Can anyone review and confirm what can be the issue here. The role status in administration shows as complete