A ProPublica investigation (March 2023) revealed Cigna's PxDx system auto-denied over 300,000 insurance claims in a 2-month window. Internal documents showed company doctors were explicitly told to batch-rubber-stamp the AI's decisions, averaging 1.2 seconds per 'review' — one doctor processed 60,000+ denials in a month without opening any medical file. The class-action suit revealed the AI was optimized purely to minimize payouts, not accuracy. Cigna denied wrongdoing but paid $172M to settle.