Cross-Chain Replay Inflation: Deterministic Supply Duplication in Interoperable Stablecoin Systems

Cross-chain interoperability has become a core requirement for stablecoin scalability. However, bridge-based transfer mechanisms introduce a critical vulnerability: Cross-Chain Replay Inflation. This failure mode occurs when mint, burn, or lock events are replayed, duplicated, or inconsistently finalized across multiple chains, resulting in synthetic supply expansion without corresponding collateral backing. This paper formalizes replay inflation as a deterministic enforcement failure rooted in asynchronous settlement and non-canonical state verification. We demonstrate why message-passing security and cryptographic proofs alone are insufficient and propose a validator-mediated enforcement layer that restores global supply coherence under MiCA-aligned compliance expectations.