Polymarket has launched its CLOB V2, introducing new features such as the Polymarket USD collateral token and an updated order book system. The upgrade aims to tackle the persistent issue of "ghost orders," which occur when trades appear executed off-chain but fail to settle on-chain. V2 removes the exploitable nonce mechanism and refines order cancellation processes, reducing the scope for attackers to disrupt trades. Despite these improvements, the fundamental model of off-chain matching and on-chain settlement remains unchanged, meaning ghost orders are not entirely eradicated. The update also includes enhancements like the new CLOB-Client SDK and support for signature 1271, facilitating smoother integration for market makers and institutional users. Polymarket's V2 marks a significant step towards improving system stability, though ongoing updates will be necessary to fully address underlying vulnerabilities.