paypal4 Hi
I think there is a bit misunderstanding here.
1/ With the palette 'Primary', you should go to Layout settings >> navigation to section you want to set and assign this palette to it.
2/ However, when you add 'bg-primary' class for this 'Our Projects' module, this class is declared with its own background color so it overrides the background color '#1f5a66' that you set in the palette.
You can simply remove this class in module and it will inherit the correct background color of palette.
Regards