According to IIA guidance, when would an interim report typically be produced?

According to IIA guidance, interim reports are typically produced during lengthy audit engagements that involve several organizational units. These reports help keep management informed about the progress of the audit, highlight any significant issues identified early on, and allow for timely corrective actions. Interim reports facilitate communication between the internal audit activity and management, ensuring that any critical issues are addressed promptly rather than waiting for the final report.

The Institute of Internal Auditors (IIA) Practice Guide on "Audit Reports"

IIA Standard 2410 – Criteria for Communicating: "Interim reports may be used to communicate information and issues that require immediate attention."