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Laptop hardware causing Linux screen brightness to misbehave

I have Linux Lite installed (after using Lubuntu for a couple of years) on my 10 yr old Laptop (Sony Vaio).
The problem started from Lubuntu and I removed it in vain, since the problem has not resolved with the new distro.

My screen starts flickering abruptly.

Initially I thought (later proved correct) that my screen flickered or stopped flickering while changing angles of my laptop display. Maybe a loose connection. Not confident in hardware repair, I have tried my hand at every command to correct screen brightness – xbacklight, changing backlight and acpi settings, bash.rc, grub command line options – everything.
At certain screen angles, reducing brightness by software slider increases flickering, and at other angles it just ignores brightness slider and sets itself at max brightness. Since 2012 I have used “sudo tee | echo backlight/brightness” command successfully.

Does this seem like a hardware bug?