According to Blockworks, the Optimism mainnet blockchain experienced a series of failures and instabilities on February 15, 2024, which began at around 6 a.m. EST. The team began investigating reports of "unsafe head stalls," meaning that the sorter stopped generating blocks. Shortly afterwards, at 6:10 a.m. EST, developers identified the cause of the problem and applied a fix that temporarily restored operations. However, this solution did not last long; by 6:26 a.m. EST, reports of additional instability questioned the effectiveness of the patch. The Optimism sorter is still centralized, which means that OP Labs is responsible for identifying and resolving issues. After finding the suspected root cause, the network recovered at around 8 a.m. EST, and the status page noted that the incident was not related to the planned suspension of OP mainnet withdrawals, which was an ongoing planned maintenance.