Plugin Help Can't change settings in "world.yml" file, PlotSquared

Hi, I made my plot world with the bridge template, and everything was ok until I realized that I couldn't drop items outside of a plot or in an unclaimed plot. So I figured out that I could fix it adding "misc_spawn_unowned" to true in the world.yml file, but I'm having a serious problem with world.yml file that everything I change or add in that file, It doesn't change nothing, Even if I do it with the server turned off, or reload the plugin, I can't change anything in the world.yml, I know it because I tried changing other setting and it didn't work. The changes that I did still being on the world.yml but it doesn't seem to work in the server, so I basically want to add "misc_spawn_unowned" to true in the world.yml, but I don't know how.