Bitcoin had a stale block on Monday at the block height of 614,732, according to BitMEX Research.
A stale block – the one which is no longer part of the current best blockchain because it was overriden by a longer chain – was last observed on Oct. 16, 2019.
Stale blocks occur when miners located on other ends of the globe solve the same block at the same time butter not picked up into the blockchain due to a time lag in the acceptance of the block in question.
When nodes are geographically closer, they pick up the block that was mined near them, leading to a small fork. The correct block, however, is quickly accepted into the main chain.
Monday’s stale block had a size of 0.98 MB and resulted in a $3 double spend. The block was mined in less than half a second after the block mined by BTC.com was mined by Poolin and then orphaned (declared stale).