God,I need to confess that I hate it when it comes to a chinese user_login with wordpress!
Whenever a user tries to edit and update his profile, the user_nicename(which is so important because wordpress use it as the slug in an author link) will mysteriously slip away.Tried so many workarounds in vail.
I guess you just can't let user edit his profile in front-end when a chinese user_login is around!
So I really need to change the default behaviour of the author link.But It's easy said than done!
Finally inspired by a plugin called edit author slug ,I came up with this http://wordpress.stackexchange.com/questions/252920/wordpress-404-not-found-after-rewrtie-the-author-link/252944#252944
So I just make user_id be the user_nicename and now my author link looks sth like /user/user_id and every body is happy!