Marathon Digital mined an invalid #Bitcoin block on Wednesday, causing the firm to miss out on newly minted BTC it would have otherwise earned. An invalid block is one that violates #Bitcoin’s consensus rules, and is therefore rejected by network nodes. Marathon did not specify how its block was invalid, though some onlookers attributed the problem to a transaction ordering issue.

Source: decrypt.co/199005/marathon-mined-an-invalid-bitcoin-block-heres-what-that-means