Cannot Control Keyboard Backlight With FN combination keys

I have a newly bought ASUS TUF FX505GD with backlit keyboard. It came with WIN10 preinstalled but installed Ubuntu 18.04 LTS alongside it. But unfortunately right after installing ubuntu I noticed I could no longer control my keyboard lights. FN + <Up Arrow> or FN + <Down Arrow> doesn't work. But the interesting thing is that right after boot the keyboard lights stays lit untill I try to control them with FN + <Up Arrow> or FN + <Down Arrow>. All other combination keys of FN works fine such as LCD brightness , Sounds etc.

• I also checked the /sys/class/leds/ folder , it only contains asus-wireless::airplane, input4::numlock, phy0-led, input4::capslock ,input4::scrolllock no sign of *kbd_backlight folder. I've searched the whole system but there is no folder with that name.

• also tried the sudo /etc/acpi/asus-keyboard-backlight.sh but it doesn't work.

• xset led 1 or xset led 3 doesn't work either.

output of $ cat /proc/version :

`Linux version 5.0.0-37-generic (buildd@lcy01-amd64-023) (gcc version 7.4.0 (Ubuntu 7.4.0-1ubuntu1~18.04.1)) #40~18.04.1-Ubuntu SMP Thu Nov 14 12:06:39 UTC 2019`

Information/specs of my laptop model :

https://www.asus.com/in/Laptops/ASUS-TUF-Gaming-FX505GD/specifications/

Update (25 January):

Three days ago I got an Software Update for Ubuntu. After that, this issue was solved , I just noticed today ?