The project manager should use the collaborate/problem solve technique to resolve this issue, as it involves finding a mutually beneficial solution that satisfies the interests of both the senior and junior team members.
This technique is also known as confronting or integrating, and it is the preferred technique for managing conflicts on a project. The project manager should facilitate a constructive dialogue between the two team members, identify the root cause of the conflict, and help them reach a common understanding and agreement. This way, the project manager can maintain a positive team environment and foster collaboration and trust among the team members. References: (Professional in Business Analysis Reference Materials source and documents) PMBOK Guide 6th Edition, page 368, section 9.5.2.1 PMI Practice Standard for Project Risk Management, page 37, section 3.5.2.1 PMI Professional in Business Analysis (PMI-PBA) Examination Content Outline, page 13, section 3.2.1.1

According to the Agile Practice Guide, a prioritized backlog is a list of features, functions, requirements, enhancements, and fixes that are prioritized according to the value they deliver to the customer and the amount of work required to complete them. A prioritized backlog helps the project team to manage changing scope and expectations in an agile environment, where new knowledge and feedback are continuously incorporated into the project. By defining iteration review sessions with stakeholders, the project manager can ensure that the project outcomes are aligned with the business goals and that the stakeholders are satisfied with the deliverables. Iteration review sessions are meetings where the project team demonstrates the work completed in an iteration and solicits feedback from the stakeholders. Iteration review sessions help to validate the value of the deliverables, identify any defects or issues, and adjust the backlog for the next iteration. References: Agile Practice Guide, pages 37-38, 5.1.1 Prioritized Backlog, 5.2.2 Iteration Review.

In an agile project, transparency and communication are key. When a team member anticipates a delay, it is important to discuss the issue openly with the team as soon as possible. This allows the team to understand the potential impact on the project and to collaborate on finding a solution. The agile methodology encourages daily meetings for this purpose, making it the ideal setting to address such concerns. This approach is supported by the PMBOK Guide, which emphasizes the importance of communication and stakeholder engagement in project management. Additionally, the Professional in Business Analysis (PBA) reference materials highlight the value of addressing issues promptly and collaboratively in an agile environment.
PMBOK Guide - Sixth Edition; Professional in Business Analysis (PBA) Reference Materials.

The project manager is responsible for ensuring that all necessary knowledge transfer has occurred prior to project closure. This includes capturing lessons learned, documenting project experiences, and updating the organizational process assets (OPAs). This ensures that the knowledge gained from the project is not lost and can be used for future projects. The project manager plays a crucial role in facilitating this process and ensuring that all team members contribute to the knowledge transfer. References: PMBOK Guide - Sixth Edition (Page 123, 4.4.3.1 Organizational Process Assets Updates)

According to the PMBOK Guide, 7th edition, one of the principles of project management is to support team performance. This means that the project manager should foster a collaborative project team environment, build team competencies, and address and remove impediments, obstacles, and blockers for the team. In this scenario, the project manager should provide appropriate training to the team members who lack the necessary skills or knowledge to perform their tasks, rather than emphasizing deadlines, updating the schedule, or accepting the risk. Providing training will help the team improve their performance, deliver value, and meet the expectations of the steering committee and other stakeholders. References: PMBOK Guide, 7th edition, page 9, Principle 8: Support team performance.