Cel-shade material looks different after package?

Hi, I’ve been having problems with packaging my game recently. It looks different after the packaging process. I am using post process material to achieve a cel shaded look ( - this one) but when I package the project it just looks like default ue4 shadows are kind of mixing with shadows from the material? Also it gets less bright. Could somebody help me with this, please?

Left - in engine, Right - standalone