https://bugzilla.redhat.com/show_bug.cgi?id=703060

As stated there, the workaround provided by the fix for bug #643350 doesn't work in fa locale and causes gnome-shell to crash. These are the error messages in xsession-errors file, which is clearly caused by the patch:

** Message: applet now removed from the notification area
    JS ERROR: !!!   Exception was: Error: Argument 'text' (type utf8) may not be null
    JS ERROR: !!!     lineNumber = '0'
    JS ERROR: !!!     fileName = 'gjs_throw'
    JS ERROR: !!!     stack = '("Argument 'text' (type utf8) may not be null")@gjs_throw:0
()@/usr/share/gnome-shell/js/ui/dateMenu.js:189
()@/usr/share/gnome-shell/js/ui/dateMenu.js:148
DateMenuButton()@/usr/share/gnome-shell/js/ui/dateMenu.js:44
()@/usr/share/gnome-shell/js/ui/panel.js:950
Panel()@/usr/share/gnome-shell/js/ui/panel.js:810
start()@/usr/share/gnome-shell/js/ui/main.js:151
@<main>:1
'
    JS ERROR: !!!     message = 'Argument 'text' (type utf8) may not be null'
ﻪﺷﺩﺍﺭ ﻡﺩیﺭ پﻦﺟﺮﻫ<200c>ﻫﺍ: Log level 32: Execution of main.js threw exception: Error: Argument 'text' (type utf8) may not be null

For whatever reason, shell_util_format_date doesn't return a valid string in fa locale and apparently, returns NULL.