A system migration project is in its closing stage.

According to the PMBOK Guide, the project manager is responsible for managing the project work and ensuring that the project objectives are met. One of the processes in the project management process group is Monitor and Control Project Work, which involves tracking, reviewing, and reporting the progress and performance of the project, as well as identifying and resolving issues. The project manager should use the issue log, a project document that records and tracks the issues that arise during the project, to document the issue of the missing notification and assign it to the appropriate project team member(s) for resolution. The project manager should also communicate the issue to the relevant stakeholders and update the project management plan and other project documents as needed. The project manager should not close out the project until the issue is resolved and the system migration is completed for all departments, as this would compromise the quality and scope of the project deliverables. The project manager should also not escalate the issue to the project sponsor and upper management, as this would indicate a lack of control and responsibility for the project. The project manager should also not report the issue during the next status meeting at the end of the week, as this would delay the resolution and potentially cause more problems for the project. The project manager should act promptly and proactively to address the issue and ensure the project is closed successfully. References: (Professional in Business Analysis Reference Materials source and documents)

PMBOK Guide, 6th edition, Chapter 4: Project Integration Management, Section 4.6: Monitor and Control Project Work, p. 123-127

PMBOK Guide, 6th edition, Appendix X1: Agile, Iterative, Adaptive, and Hybrid Project Environments, Section X1.5.2: Issue Log, p. 715

Business Analysis for Practitioners: A Practice Guide, Chapter 5: Traceability and Monitoring, Section 5.3: Monitoring the Performance of Business Analysis Work, p. 143-144

The PMI Guide to Business Analysis, Chapter 7: Solution Evaluation, Section 7.3: Assess Solution Limitations, p. 373-374