I just updated my instance to exactly the same version, and it looks correct.
I am curious if your assets are cached.
If you are using Google Chrome, could you please go to the inspector and open the “Sources” tab?
You should be able to see a link to the zh_CN/admin.js file.
Then, if you copy and paste that link into another tab, can you please check if you have the dashboard translations?
Sorry for the quite technical debugging. The bug you are experiencing is quite unusual.