When a consultant requests changes to a software component during an iteration, claiming it does not meet market requirements, the project manager should continue the iteration and review the change with the customer. This action ensures that the iteration's progress is not halted while also addressing the consultant's concerns. It is essential to involve the customer in the decision-making process since they have a vested interest in the product's success and alignment with market needs. This approach is consistent with the principles of stakeholder engagement and communication found in both PMP and business analysis best practices.
References:
The PMBOK Guide, which outlines the project management framework, emphasizes the importance of stakeholder engagement and communication throughout the project life cycle1.
The PMI Professional in Business Analysis (PMI-PBA) guide highlights the role of business analysts in facilitating communication between stakeholders and ensuring that project outcomes align with business needs23.
Discussions among PMP professionals suggest that addressing changes without disrupting the current iteration's workflow is a common practice, and customer involvement is crucial

According to the Agile Practice Guide, one of the principles of agile project management is to "build projects around motivated individuals. Give them the environment and support they need, and trust them to get the job done" (Section 2.1). This implies that the agile project manager should foster a collaborative and self- organizing team culture, where team members share their knowledge and skills with each other, and are able to adapt to changing situations. By asking the team member to work with their peers to knowledge share, the agile project manager can ensure that the team has the necessary information and expertise to continue working on the project, even when the specialized team member is unavailable. This is also consistent with the PMBOKGuide, which states that "the project manager should facilitate knowledge sharing among the project team and other stakeholders" (Section 4.4.3.3). References:
* Agile Practice Guide, Section 2.1
* PMBOKGuide, 6th Edition, Section 4.4.3.3

According to the PMBOK Guide 6th Edition, the project manager should provide the failed test results along with the agreed-upon acceptance criteria to support their claim to the vendor. This is because the acceptance criteria are the measurable and verifiable standards that define the quality requirements of the project deliverables. The project manager and the vendor should have agreed on the acceptance criteria before signing the contract. Therefore, providing the failed test results along with the acceptance criteria will show the vendor that they have not met their contractual obligations and that they need to take corrective actions to improve the system quality. References: PMBOK Guide 6th Edition, page 161, section 5.5.2.1; page 287, section 8.2.2.1; page 375, section 12.1.2.1.