You discover that a production data pipeline feeding executive dashboards and downstream model evaluation reports has started producing incorrect numbers. The issue was first noticed after a weekly business review, and several teams now question whether recent reporting based on the warehouse is reliable. You need to investigate the root cause, contain the impact, communicate clearly to stakeholders, and decide how to restore the pipeline safely without creating more downstream inconsistencies.
Describe a time when you had to troubleshoot a data pipeline issue. How did you diagnose the problem, manage stakeholders, reduce business impact, and ensure the issue would not happen again?