The default file sort (name or last updated) can not be saved as a default. When refreshing the page it goes back to the last sort that you used on the "All Files" page.
Similar to other online file sharing platforms, when you change teh default sort to name or last modified it saves that sort for all other folders. On Box.com if you change the default sort to by last modified on the All Files page it then applies that as the default sort for all other sub folders. I found this bug with Box support after entering a ticket. They suggested I report the bug here. Case 2744369