The technical lead should follow the escalation path. The issue described is a performance/response problem that is impacting delivery while the PM is unavailable. CompTIA Project+ emphasizes having and using an escalation path as part of issue management and governance, ensuring problems are raised to the correct authority quickly (e.g., acting PM, functional manager, HR/people manager, or sponsor depending on severity and policy). Escalation is appropriate because the team needs timely intervention to restore progress and accountability.
Updating the issue register (B) is a useful documentation step, but it does not by itself resolve the problem; escalation drives action. Informing all stakeholders (A) is usually excessive and can create noise or reputational harm; stakeholder communication should be controlled and targeted, typically after escalation determines impacts and a recovery approach. Initiating a change request (D) is inappropriate because the core problem is not a requested change to scope or requirements; it is a delivery/behavior issue requiring management intervention.
A good escalation approach is: document facts (missed deliverables, non-responsiveness), attempt direct contact, then escalate per policy to the designated backup PM or functional manager for corrective action (reassign work, coaching, or formal performance steps).