Marathon Digital Holdings, a leading Bitcoin mining company, has reportedly mined an invalid Bitcoin block at height 809478 due to a transaction ordering issue within its mining pool, MaraPool. The problem was first identified by an anonymous Bitcoin developer known as 0xB10C, who suggested that Marathon Digital might have been running custom code that deviated from established practices. Jameson Lopp, co-founder of CasaHODL, and BitMEX Research, a well-known cryptocurrency research firm, both confirmed the incident. Marathon later acknowledged the reports.