This 51% attack strongly emphasizes the need to fork off the Z9 Asics.
Guess Zen devs could not be bought over by Bitmain unlike Zooko of Zcash, unhappy, they probably started the attack as a warning.
(Complete speculation but it makes sense)
"The Zen team will continue monitoring the network and conducting forensic analysis with the affected exchange. All information gathered will be provided to the appropriate authorities."
It is too early to point finger on Asic, we are investigating.