Marathon reportedly mined an invalid Bitcoin block

Marathon Digital Holdings (MARA), a publicly traded crypto mining company, reportedly mined an invalid block on Bitcoin, according to developers, miners and researchers

The invalid block was at height 809478, with anonymous Bitcoin developer “0xB10C” writing on ooX that MaraPool — Marathon’s mining pool — had a “transaction ordering issue.”

This was confirmed by Casa CTO Jameson Lopp, who said that data gathered from all nine of his nodes shows that the block contained a transaction that incorrectly spent an output before it was created, thus invalidating the block.

Other Bitcoin node operators rejected the invalid block.

According to BitMEX Research, the issue arose because a transaction in the block was ordered incorrectly in relation to a spending output transaction, breaking consensus rules.

When a miner produces an invalid block, nodes running the Bitcoin protocol will reject and not build on top of it. Miners are incentivized to construct valid blocks according to consensus rules, as invalid blocks represent wasted resources and reward loss.

Marathon Digital operates a large mining operation with over 37,000 active miners and 3.2 EH/s of hash rate. However, this incident illustrates that even major mining pools are susceptible to consensus rule violations that lead to wasted mining effort.

The event appears to be a minor hiccup that demonstrates the resilience of Bitcoin’s decentralized proof-of-work consensus mechanism.

Even major miners must follow network rules and properly structure blocks, or their work will be rejected by the peer-to-peer network.