Event-Spread Perpetuals under Asynchronous Finality: Joint-State Risk, Residual Exposure, and Settlement Design

An event spread links two bounded claims, but its legs need not become final at the same time or through the same state path. Once one leg is final, the contract becomes a residual single-leg exposure whose risk depends on the finalizing leg and payout. This paper develops formal and empirical designs for asynchronous Oracle, adapter, protocol, and realization states. A condition-level census identifies descriptive asynchronous finality among exact same-event candidate pairs, but not semantic payoff restriction or executable residual liquidity. The work distinguishes formal multi-leg results from observed pair-level timing and operational claims that require stronger evidence.