Software development is inherently a human activity, and human errors made by software engineers are a significant root cause of software faults and vulnerabilities, posing risks to the trustworthiness of software systems. Post-Completion Error (PCE) is a human error pattern observed in operators such as pilots, air traffic controllers, and train conductors. Previous experimental research has demonstrated that this systematic error is also highly prevalent in software development. However, there is a lack of research on how PCE causes and manifests as diverse software faults and vulnerabilities in real-world industrial projects. This paper presents two in-depth analyses of industrial data, providing 11 concrete examples and detailed Error-Prone Scenario maps. These results represent the first valuable dataset on post-completion errors in software engineering. The findings equip practitioners with actionable strategies for identifying and mitigating this human error mode across diverse industry settings.