You might have read about the Hallyu ban in China here and even if you haven't, you might have heard about it elsewhere because it's being talked about even though no one seems to know exactly what is going on.
***** If you don't want to read the translations, skip to the END.
The ban 限韩令 actually has its own page on Baidu where it states, "After Korea's deployment of THAAD, a US anti-ballistic missile system, it is said that the Chinese government has imposed limits on Korean celebrities and shows, including a ban on group performances by Big Bang, EXO, etc... and a blacklist on Korean dramas, variety shows, and celebrities effective September 1."
Nevertheless, a spokesman from the Chinese Department of Foreign Affairs comments, "First of all, I haven't heard of the Hallyu Ban. Second, we have always taken a supportive stance when it comes to a cultural exchange between China and Korea though its success is dependent on the support of the public. Third, China remains firmly against the move by the US to deploy THAAD in Korea."*****END
To sum up the long spiel, a guy from China's Department of Foreign Affairs denies knowledge of a Hallyu ban though he seems to insinuate that the nation's united stance against THAAD will ultimately affect the public sentiment on the Korean wave.
It sounds serious and all but we know the ban hasn't happened with a number of k-dramas such as Moon Lovers recently airing in China. I doubt that a complete ban will ever be enforced, though it's likely that it will be done behind the scenes and in small waves.
The crackdown seems to be in progress as Yoo In Na who confirmed for Shuttle Love Millennium was quietly replaced by Puff Guo while Korea's superstar Song Joong Ki who signed a multimillion dollar (approx RMB 22 million) product endorsement with Vivo in May was also recently replaced by Eddie Peng. It's not all bad because Song gets to keep the money and we get Eddie.
Jun Ji Hyun faces a similar situation after signing a deal with Oppo last month only to be replaced by Angelababy. As a third party from the outside looking in, the whole thing just sounds wrong.