The best course of action for an IS auditor who finds that some critical recommendations have not been implemented is to evaluate senior management's acceptance of the risk. The IS auditor should understand the reasons why the recommendations have not been implemented and the implications for the organization's risk exposure. The IS auditor should also verify that senior management has formally acknowledged and accepted the residual risk and has documented the rationale and justification for their decision. The IS auditor should communicate the findings and the risk acceptance to the audit committee and other relevant stakeholders. References:
CISA Review Manual (Digital Version)
CISA Questions, Answers & Explanations Database

The greatest risk to an organization's ability to manage QC processes is the lack of policies and procedures that define the QC objectives, standards, methods, roles, and responsibilities. Without policies and procedures, the QC processes may be inconsistent, ineffective, inefficient, or noncompliant with the relevant regulations and best practices. Policies and procedures provide the foundation and guidance for the QC processes and help to ensure their quality, reliability, and accountability.
References
ISACA CISA Review Manual, 27th Edition, page 253
Quality Control - an overview | ScienceDirect Topics
Quality Control: Meaning, Importance, Definition and Objectives

The best way to facilitate the legal process in the event of an incident is to preserve the chain of custody of the evidence. The chain of custody is a record of who handled, accessed, or modified the evidence, when, where, how, and why. The chain of custody helps to ensure the integrity, authenticity, and admissibility of the evidence in a court of law. The chain of custody also helps to prevent tampering, alteration, or loss of evidence that could compromise the investigation or the prosecution. References:
* CISA Review Manual (Digital Version)
* CISA Questions, Answers & Explanations Database