After last weekend when I launched the game all of the settings were changed to default (not the first time) as windowed screen in graphic settings, but this when I changed it back to full screen it didn't allow me to change resolution for my screen's resolution of 1920x1080 but of highest value of 1600x1024, any tips?

It's hiding below, I remember having similar trouble. For me it was there but wouldn't show up not sur about this but I think it was something like a dropdown menu that didnt go to the bottom of the possibilities so I used the "elevator" thing by clicking on it instead of using the wheel. Or it only shows up when in full screen, didnt really pay attention to this but its an easy fix.

I encountered this too...it's indeed an "easy fix". To change the resolution, just change it to the highest value it gives you and then you will be able to scroll down again(don't use the wheel on your mouse). This worked for me.

you can also use the launch options: -resx=1920 -resy=1080

found it, it's fuckin annoying when the set everything on default includinh audio and game settings -.-