Why does the preprocessor (prepros) save the sprite in a different color?

Question

Layout

In Photoshop, the color is like this

And after processing by the preprocessor, like this

That is, the preprocessor apparently saves the sprite in a different color mode.
Please tell me how to overcome this trouble. The Prepros
utility is used as a preprocessor PS: here are the sprite settings from the config

@import "compass/utilities/sprites";
$icons-spacing: 20px;
$icons-sprite-dimensions: true; 
@import "icons/*.png";
@include all-icons-sprites;