According to IIA standards, assigning an auditor to review an area where they previously had responsibilities may compromise objectivity. The best approach is for the auditor to abstain from participation in the audit of the collections unit to avoid any perceived conflicts.

Including NGO members on an assurance team when auditing corporate social responsibility adds credibility to the audit findings, particularly when these findings are positive. NGOs are generally perceived as independent and dedicated to public interest, which can enhance the perceived impartiality and trustworthiness of the audit results in matters related to social responsibility.
Institute of Internal Auditors (IIA) - Advisory on Assurance Engagement for Corporate Social Responsibility

It would be considered problematic for the chief audit executive (CAE) to provide assurance services over the payroll function if, prior to becoming the CAE, the CAE was the payroll manager. This scenario poses a conflict of interest and impacts the objectivity required for assurance services, as the CAE might have inherent biases or a conflict due to previous roles and responsibilities within the payroll function.
The Institute of Internal Auditors (IIA) - Code of Ethics and International Standards for the Professional Practice of Internal Auditing.

To assist the board in gaining a better understanding of the degree of ethics awareness within the organization, the most appropriate action would be to request the internal audit activity to perform an ethics-related assurance engagement. This type of engagement would directly assess the organization's ethical culture and practices, providing the board with a detailed and objective evaluation of ethics awareness and related issues throughout the organization.
IIA's guidance on the role of internal auditing in organizational ethics.

Appropriate disclosure of nonconformance with the Standards is demonstrated when the chief audit executive (CAE) discusses with the board issues regarding the internal audit activity performing an IT engagement without proper skills and knowledge. This direct communication with the board about significant issues affecting the internal audit function's ability to conform to professional standards is crucial for ensuring accountability and transparency.
IIA Standards on communication and disclosure of nonconformance.