Model Drift Alerts After a Feature Pipeline Change: My Debugging Notes

A few weeks ago our model monitoring started firing drift alerts every morning around 7:30. The model scored customer support tickets for escalation risk, and the alert said the feature distribution had moved hard from the training baseline. At first it looked like a real production issue because PSI jumped on ticket_age_hours, agent_queue, and last_contact_channel all at once. The confusing…