The team architect resigned from the company.

 The project manager should request an architecture review as the first step to address the design flaw that may potentially impact the final quality. An architecture review is a process of evaluating the design of a system or a product against a set of criteria, such as requirements, standards, best practices, and quality attributes. An architecture review can help to identify and resolve design issues, risks, and gaps, as well as to ensure alignment with the project objectives and stakeholder expectations. By requesting an architecture review, the project manager can involve the relevant experts, such as the new architect, the previous architect (if possible), the quality assurance team, and the customer, to assess the impact of the design flaw and to propose and agree on the necessary changes. This will also help to update the project scope, schedule, cost, and quality baselines accordingly. References:

Architecture Reviews - an overview | ScienceDirect Topics

Architecture Review Process - SEBoK

Architecture Review - The Open Group

Design Flaw Attacks - an overview | ScienceDirect Topics

DESIGN FLAWS: FLAWS BY DESIGN? / The Design Society