functional incompetence

The ability to maintain a façade of competence, the surface of which, once penetrated, reveals the individual actually has little to no understanding of the tasks in which they have been placed in control of. This type of employee is of particular concern as their incompetence may not be discovered until they have left the organization.

John excelled at functional incompetence because he seemed to know what he was doing until an audit showed he fabricated all his reports.