When a risk materializes and becomes an issue, the project manager should work with the relevant stakeholders to implement the risk response plan that was prepared during the project's planning phase. This is in line with the PMI's principles, which suggest that risks should have predefined response plans that can be activated when they occur. The implementation of the risk response plan is a proactive step to address the issue and mitigate its impact on the project1.
References:
* Project Management Institute (PMI) standards and publications.
* PMBOKGuide - Sixth Edition.
* "Plan Risk Response for Your Projects" - Project Management Academy2.
* "PMP Exam Strategies for Risk Response: Mitigate Risk, Avoid, or Transfer" - Project Management Academy3.
* "Risks vs Issues: Why most projects fail" - PMI4.
* "The Difference Between Risk and Issues in Project Management" - iZenBridge5.

After resolving quality issues with deliverables, it is essential for the project manager to conduct a lessons learned session. This process is part of the knowledge area of Project Quality Management, which emphasizes the importance of continuous improvement. Conducting lessons learned helps the team understand what went wrong, why it went wrong, and how similar problems can be prevented in the future. It is a proactive step to enhance the quality of future deliverables and processes.
References:
A Guide to the Project Management Body of Knowledge (PMBOK Guide) - Seventh Edition1.
PMI Professional in Business Analysis (PMI-PBA) Reference Materials2.

To avoid the situation where stakeholders are not aware of changes in project requirements, it is crucial for the project manager to ensure that communications are sent to all stakeholders when requirements change.
This involves clear documentation and dissemination of information regarding any alterations to the project's scope or equipment needs. Effective communication helps in managing stakeholder expectations and prevents misunderstandings about project deliverables123.
References:
Changing Requirements in Project Management: How to Stay on Track1.
Techniques to Communicate Effectively with Project Stakeholders2.
Engaging Stakeholders Who Keep Changing Project Requirements3.

Earned value (EV) is a technique that measures the performance of a project by comparing the actual work completed with the planned work. It can help the PMO to report the project's health in terms of schedule and cost variance, as well as the schedule and cost performance index. EV can be applied to both predictive and adaptive (agile) projects, as long as the project scope, schedule, and budget are defined and measurable. The PMO can use agile progress, such as the number of features delivered, user stories completed, or story points earned, as an input to calculate the EV KPls. This way, the PMO can provide upper management with the traditional reports that they are used to, while also reflecting the agile nature of the projects. References:
A Guide to the Project Management Body of Knowledge (PMBOK Guide) - Sixth Edition, Chapter 7, Section 7.4.2.1 Practice Standard for Earned Value Management - Second Edition, Chapter 3, Section 3.2.3 Agile Practice Guide, Chapter 5, Section 5.4.2