Hi!

I have a 2019 Asus Zenbook 14 (UX434FLC, Comet Lake version), this happened ~2 months ago but is annoying me.
So, I decided to update from 203 to 303 using EZ Flash option in the BIOS. Everything went fine to 100%, the laptop restarted to black screen, stood there for about 30 seconds, restarted again and booted Windows.
Everything works fine under running OS and inside BIOS too, but since the update, it has some weird issues with keyboard backlight, and the fan. Sometimes when I turn the laptop off from the OS, the keyboard backlight stays on at full brightness, doesn't matter what level was set in Windows. If I restart it before shutting down, it has more chance to act like this. Pulling out the charger makes the keyboard backlight turn off, otherwise it stays on forever, or until next start.
The other issue is, when I plug in the charger to laptop, its fan starts spinning for a second, while its off. Under running Windows, sleep mode, this doesn't happen, neither the keyboard backlight issue.

Everything else is okay, everything is stable, no crashes, no freezes, just these weird issues. I have flashed the original unmodified BIOS from Asus's support page. I did load defaults, did EC reset, nothing changed.
What could cause this behavior? I think there will be more updates in the future, but I don't want to brick it or something. Nothing new BIOS version has released yet, but I don't know if is it safe to update the BIOS in this condition, or not.
In the changelog, it says "Upgrade BIOS to improve the user experience of ScreenPad 2.0/Plus while system resume.", can a bug in the BIOS cause behavior like this, or there is something gone wrong on my laptop?

Link to the support page from where I downloaded the 303 BIOS to update from 203: https://www.asus.com/Laptops/ASUS-ZenBoo.../HelpDesk_BIOS/

Thanks a lot for help, and sorry for the off-topic! :)