Quarterly update impacts on custom job roles

Summary:

We are currently running a complex J2C program that requires an high level of customization in job roles.

We need to create many custom roles in ERP (both on FINANCE and SCM). Considering that such customization will affect all the roles related objects (duty roles privileges) we need to understand if once privileges are removed from the custom job roles (created from scratch or cloned by a seeded role), do they come back with the next quarterly update?

As per our understanding there will be no effect when all the layers behind a role are customized, but what happens if we are using for instance abstract role relying on "untouched" duty role?