As far as I know, there was some drama at Magical Mirai Osaka involving a small group of Chinese attendees. People accused them of things like talking loudly during the show, allegedly recording with smart glasses, and making red X signs with glowsticks during Hand in Hand. There was also an altercation where one attendee said he confronted someone for talking and was pushed.
After that, some Japanese fans started generalizing the situation toward Chinese fans as a whole, which caused another argument online about xenophobia/discrimination. Even one of the people making those comments later apologized and admitted he got emotional and generalized.