Starknet, an Ethereum Layer 2 network, reported an 18-minute mainnet outage caused by a state conflict between its execution and proving layers. The issue arose when the execution layer incorrectly recorded state writes during certain cross-function calls and rollbacks, leading to abnormal transaction execution. As a result, affected transactions did not receive finality confirmation on Layer 1, prompting a blockchain reorganization. This incident marks Starknet's second major disruption since 2025, following a September outage due to a sequencer vulnerability that resulted in over 5 hours of downtime and a rollback of about 1 hour of on-chain activity.