I remember when Ryan Li 1p beat Chen Yaoye 9p in a tournament game (June 21, 2017).
Chen Yaoye 9p lost to Ryan Li 1p - General Go Discussion - Online Go Forum (online-go.com)
(I hope this is right. I’m counting from @GreenAsJade’s June 29, 2017 post above. @bugcat posted something from May 2017 just before that, however.)