The strangest thing just happened: I had closed my Apple Music tab and when I returned to music.apple.com (still logged in, mind you) everything was in Chinese (confirmed by "cn" in the URL). I tried going to music.apple.com (no "cn" in the URL) and got the Chinese version again. I have never been to China in my life or used a VPN with servers in China. I don't have any connection to China at all.