The PMBOK® Guide emphasizes the importance of clear and effective communication in project management. When a project manager notices that a client team member frequently halts progress due to misunderstandings, it is crucial to address the communication gaps. Updating the communications matrix to include this team member ensures that they receive all necessary information and understand their role and the project elements. This action aligns with the best practices for project communication management, which advocate for inclusive and comprehensive communication plans that cater to all project stakeholders12.