In this scenario, the supply manager's primary mistake was failing to communicate with the user departments to assess the impact of the defective shipment before terminating the purchase order. Leadership and transformation management documents emphasize the importance of stakeholder communication and impact assessment in decision-making processes. The supply manager should have validated the defect and discussed potential solutions with the affected departments to understand the full impact of the issue and to explore possible remediation steps, such as requesting a replacement shipment or working with the supplier to resolve the quality issue. Immediate termination without such consultation could lead to unnecessary disruptions and a lack of alignment with organizational needs. Reference from leadership literature highlight the importance of cross-functional communication and collaborative problem-solving in supply chain management.