The casino is setting up identically to August 2015. The only problem for gamblers is that it's not 2015.
The week of August 20th was options expiration.
Bueller?
The proximate catalyst for the 2015 flash crash was Yuan devaluation which was in fact preceded by EM currency rollover:
Low volatility was reversing
Speculation was rampant
The Energy sector was imploding
Breadth was extremely weak
Europe had rolled over
Japan had rolled over
The Fed was clueless
Albeit, that's nothing unique to 2015 or now mind you
The twist of course this time is the fact that it's the end of the cycle. Time to get out of the casino...