Bitcoin: Two Simultaneously Produced Blocks - Why?
Bitcoin, in addition to being the world's most popular cryptocurrency, is also a decentralized digital currency that operates on a blockchain network.

The Bitcoin network's unique features make it highly secure and reliable, but like any technology, it is not immune to occasional hiccups. Recently, a rare event occurred on the Bitcoin network, with two different blocks being produced simultaneously. In this article, we will explore the causes and consequences of this unusual situation.
The Event Detected by ForkMonitor
According to the ForkMonitor node monitoring tool, the Bitcoin network at block height 783426 experienced the production of two blocks simultaneously. This event was noticed by BitMEX Research, who shared it on Twitter.
The simultaneous production of two blocks on the Bitcoin blockchain means that a temporary fork occurred, with two different miners producing different blocks at the same time.
BitMEX Research Findings
One of the blocks produced during this event was an invalid block that appeared to violate the BIP66 protocol rule. This rule requires that all signatures in a block be strictly DER-encoded. The invalid block was eventually rejected by the network and replaced with a valid block. F2pool, a well-known cryptocurrency mining pool that supports mining for Bitcoin and over 40 other cryptocurrencies, was responsible for producing the invalid block. The reason for F2pool producing an invalid block is still unknown and under investigation.
According to BitMEX Research, the invalid block produced by F2pool may have been due to faulty signature transactions. However, the exact cause is still being investigated.
F2pool's Invalid Block
The consequences of producing an invalid block are that it will be rejected by other nodes that follow the Bitcoin network's consensus rules. The miner who produced the invalid block will not receive any reward for it, and will have wasted their computing power and electricity.