A system of record is the authoritative source of truth for a specific type of data — the one place everyone agrees is correct if two systems show conflicting information.
Most marketing teams have a system of record for individual pieces of data (a CRM for pipeline, a CMS for page content) but lack a system of record for the state of a launch itself — whether a given campaign is approved, verified, and safe to ship. That gap is what allows the same discrepancy (a mismatched price, a broken tag) to sit unnoticed, because no single system is responsible for catching it.