Coinbase reported that newer versions of three major AI model families detected fewer fraudulent payments and less fraud value in a historical Onramp test. The evaluation replayed 16,140 transactions under an unchanged decision policy. Every newer version had lower recall, F1 and dollar-weighted recall. Coinbase separately reported stronger fraud detection from a custom model and lower production latency in different evaluations. The tests did not establish customer losses from deploying the tested model upgrades.