What should you do when you find a bug in previously delivered functionality?

When encountering a bug in previously delivered functionality, putting the bug into the Product Backlog if it is not critical is the appropriate course of action. This approach aligns with Scrum principles because it emphasizes the importance of managing work through the Product Backlog, ensuring that all issues, including bugs, are tracked and prioritized in a structured manner.

By placing the bug in the Product Backlog, it allows the Scrum Team to assess the impact of the bug relative to other ongoing work. This prioritization helps in making informed decisions about when and how the bug will be addressed based on its severity and the overall goals of the project. This practice fosters transparency and collaboration within the team and with stakeholders, as it ensures that all work items are visible and subject to the team's agreed-upon prioritization process.

Furthermore, this approach also emphasizes the importance of teamwork and communication. The team can discuss the bug during Backlog Refinement sessions, consider it in relation to other priority items, and plan for its resolution in a future Sprint if necessary. By taking this route, the Scrum Team maintains focus on delivering value incrementally while managing technical debt effectively.