Bitcoin mining vardiff controllers may cause energy waste during hashrate drops

Bitcoin Optech reported on September 18 that certain variable difficulty (vardiff) controllers used in Bitcoin mining can fail to adjust when a miner's hashrate drops abruptly. This technical weakness, initially analyzed by mining engineer Eric Price, can cause miners to continue consuming electricity while failing to submit valid shares, as the controller remains stuck on a higher difficulty target. The issue pertains to pool-assigned share difficulty rather than the Bitcoin network's overall difficulty, and it highlights a potential operational inefficiency during power curtailment events.