A deployed function looks not elegant. Is this due to design problem, or deployment is not in accordance to the design? Fixing it will be costly without retrofit.
Similarly, this happens to cyber protection. Protection effectiveness will be degraded or even none if improper design, or incorrectly deployed.
To address this pitfall, comprehensive assessment from design, configuration check before commissioning and regular health check at O&M stage are necessary. Even if the system has not been changed, the external threat landscape has evolved and need to strengthen control to protect.