Unsurprisingly, similar to the currency, the outperformance of the Chinese stock market vs. the S&P 500 falters when the Chinese currency can't be sustained. Not quite as direct of a relationship, but this clearly affects emerging markets, which are highly indebted to the dollar.
This is visible if you go back further as well - the broad rolling emerging market problems all occurred starting when the USDHKD peg was hit in April 2018. April 18th, 2018 was a pivotal day in that regard. Also, it's no surprise that EM currency problems are starting to suddenly become problematic once again....