AWS Cost Explorer showed a bug on July 16-17, 2026 that displayed massively inflated billing estimates — some customers saw invoices claiming they owed billions or even trillions of dollars for routine S3 usage, though the actual charges remained correct. Amazon confirmed the defect and fixed it, but the incident exposed gaps in how automated financial systems can mislead customers about their real costs. The post's tone suggests this is a notable systems failure worth remembering as a cautionary tale about automation and user experience in critical tools.