Several recent monthly invoices have been disputed by the client despite being clearly defined; payments have been late and outside the contracted schedule, and recent invoices were only partially paid. What should the project manager do?

The project manager should hold a meeting with the client to address the issue directly. This is a critical stakeholder relationship problem that requires immediate and direct communication to understand the client's perspective, clarify the discrepancies, and negotiate a resolution. Reviewing prior projects for lessons learned is a good general practice but doesn't address the immediate, ongoing problem. Logging nonpayment as an issue and tracking it is necessary, but it's a reactive measure that doesn't proactively resolve the root cause. Updating the procurement management plan with the project team is premature; the first step is to understand the client's position before considering internal process changes.