Coinbase-incubated Layer 2 Base stopped producing blocks for about two hours on Thursday after an invalid block stalled its chain, before the network recovered and resumed normal operation. The halt revived questions about the centralized sequencer that orders transactions on most major rollups.

Base mainnet block production turned “unhealthy” around 12:03 p.m. ET Thursday, according to the Base status page. The team identified the trigger as a problematic block interfering with subsequent block building, then isolated a consensus fault that caused an invalid block to be sequenced and blocked new blocks after height 47,806,542. Sequencing resumed by 1:51 p.m. ET, and Base confirmed healthy block building roughly two hours after the stall began.

Funds Secure

Base disclosed the incident on its own channel as it unfolded. “Base Mainnet is currently halted while the team works on an issue with block production,” the network posted on X, adding that all funds were secure and asking users to be patient while it worked on a fix.

Ecosystem node operators had to restart their nodes to recover syncing, the status page noted. Base said its long-planned Beryl hardfork still activated as scheduled at 2:00 p.m. ET, minutes after recovery. The team said it had found the root cause and would publish a full post-mortem.

Sequencer Risk

Like most leading rollups, Base settles transactions to Ethereum but relies on a single sequencer to order and produce blocks. When that component fails, the chain stops advancing even though user funds and the underlying Ethereum settlement remain intact. The design keeps assets safe but leaves liveness dependent on one operator, the failure mode that surfaced Thursday.

Base ranks among the largest Layer 2 networks by total value locked, holding more than $4 billion across protocols, per DefiLlama. That scale means a multi-hour stall ripples through decentralized exchanges, lending markets, and bridges built on the chain, even when no assets are lost.

Base has been moving to dilute the sequencer dependency. Its Azul upgrade in late May introduced multi-proofs and pushed the chain toward Stage 2 decentralization, the rollup-maturity benchmark that limits how much control any single party retains over a network.

Base did not give a timeline for the post-mortem. The chain has continued producing blocks normally since the Thursday recovery.