Wrong locale generation based on location

[Behrouz]

A successful installation of Ubuntu won't recognize true localization. This particular situation happened to me a couple of times after choosing "Tehran/Iran" in the installation menu.
The wrong locale is chosen as "az_IR" by installer while the right one is "fa_IR".

This is the true localization placed in "/etc/default/locale"

LANG="fa_IR.UTF-8"
LC_NUMERIC="fa_IR"
LC_TIME="fa_IR"
LC_MONETARY="fa_IR"
LC_PAPER="fa_IR"
LC_NAME="fa_IR"
LC_ADDRESS="fa_IR"
LC_TELEPHONE="fa_IR"
LC_MEASUREMENT="fa_IR"
LC_IDENTIFICATION="fa_IR"

Further problem happened in Ubuntu and other flavors but MATE. All had wrong calendar format based on Iranian Jalali calendar.

[Behrouz (javanmardy)]

I'm running official Ubuntu 18.04 and this bug is still there.
I should manually generate fa_IR and change the /etc/default/locale to the right value.

[Niyumard (niyumard)]

I'm using Ubuntu 18.04 too and also I have a laptop with Ubuntu Mate 19.10 and another with Xubuntu 20.04 beta, none of them correctly recognize the true locale.
I think the problem is caused by auto-recognition of locale from the Internet.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.