Citing report from ambcrypto.com, Bitcoin Cash blockchain faces glitch after the scheduled network upgrade implementing Schnorr signatures and more. It was noticed that no blocks were found after 582680; the network was stuck without the production of any blocks. The second block, after the update, took about half an hour to be produced.
The founder and CEO of the leading Bitcoin mining pool BTC.TOP, JIANG Zhuoer, expressed his opinions on the BCH upgrade via Weibo, China's Twitter. According to him, attackers made a bunch of special deals on BCH, resulting in a failure in mining new blocks; BTC.TOP has borrowed the hashrate and mined more than ten blocks after the upgrade (100% confirmation of no rollback) to ensure the successful upgrade. So, BCH has sufficient hash power; 100% confirmation of no rollback greatly guarantees the irreparable modification and safety of blockchain; special transactions take advantage of a problem in sigops checking that causes the pool to make an error in the getblocktemplate. This problem only affects the mining pool to mine new blocks, with no other harm. The mining pool has taken measures and will be back to normal later; this issue has nothing to do with this upgrade, and the attacker chose this timing for PR reasons.
According to the PeckShield security team, there is some "controversy" surrounding the BCH upgrade. This upgrade is indeed completed successfully, so far there is no exceptional situation. The elongated outputting time may be due to the fact that some BCH clients have not completed the upgrade in time resulting in small hashrate and slow block-producing speed. In the meantime, there is the possibility of such attacks like what JIANG said, but malicious attacks and BCH normal upgrade are not directly related.