BlockSec has reported a hack on the Arbitrum on-chain FutureSwapX contract, resulting in a loss of approximately $395,000. The attacker exploited the contract through multiple changePosition operations, ultimately withdrawing USDC. The exact cause remains unclear as the contract is not open source, but it is suspected that unexpected changes in stable balance during early position updates may have led to the unauthorized release of USDC. BlockSec is attempting to contact the FutureSwapX team for further investigation.