Didn't use to happen. Now happens with any upload of csv data, regardless of content (and it isn't Chinese!).
cat /etc/default/locale LANG="en_US.UTF-8"
My language settings are all English
your character set in import page is wrong and should be "UNICOE (UTF-8)"; you have,more probably as a "UNICODE (UTF-16), which is wrong!
when you try import an csv file, you should pay attention to "character set" of the import.
when you click on CSV file to open it, Libre Office open the first import PAGE and ask you how do you what to import it.
Above of this window you see the option "character set; the front of that you see a of different option of setting font as a cascade menu; you should change it and choose "Unicode (UTF-8)".
Somehow my character set had got changed from "Unicode" to "Unicode (UTF-8). Changing it back completely fixed this issue