Refresh when Editing Permalink

In post editing page, when I’m editing the permalink, it refreshes to the old one every several seconds, and all my changes are gone. This happens again and again, like every time when I try to edit the link. Now I have to write my link slug somewhere else and then paste it to permalink. What causes this, How can I fix it?

I’m using the latest version(3.8.1) of WordPress on Nginx server. My website: http://nonewz.com