Problem with warnings after compiling assets - laravel

Question

When I compile assets with command npm run prod, I'm receiving this message:
WARNING Compiled with 2 warnings
warning in ./resources/sass/app.scss
Module Warning (from ./node_modules/postcss-loader/src/index.js):
Warning
(1973:3) Error in parsing SVG: Non-whitespace before first tag. Line:
0 Column: 1 Char: d
# ./resources/sass/app.scss 2:14-253
warning in ./resources/sass/app.scss
Module Warning (from ./node_modules/postcss-loader/src/index.js):
Warning
(2084:3) Error in parsing SVG: Non-whitespace before first tag. Line:
0 Column: 1 Char: d
# ./resources/sass/app.scss 2:14-253
after this warning I get list of compiled files, and after that the warnings again. This time they seems to be more precise:
WARNING in ./resources/sass/app.scss
(./node_modules/css-loader??ref--5-2!./node_modules/postcss-loader/src??postcss0!./node_modules/resolve-url-loader??ref--5-4!./node_modules/sass-loader/dist/cjs.js??ref--5-5!./resources/sass/app.scss)
Module Warning (from ./node_modules/postcss-loader/src/index.js):
Warning
(1973:3) Error in parsing SVG: Non-whitespace before first tag. Line:
0 Column: 1 Char: d # ./resources/sass/app.scss 2:14-253
WARNING in ./resources/sass/app.scss
(./node_modules/css-loader??ref--5-2!./node_modules/postcss-loader/src??postcss0!./node_modules/resolve-url-loader??ref--5-4!./node_modules/sass-loader/dist/cjs.js??ref--5-5!./resources/sass/app.scss)
Module Warning (from ./node_modules/postcss-loader/src/index.js):
Warning
(2084:3) Error in parsing SVG: Non-whitespace before first tag. Line:
0 Column: 1 Char: d # ./resources/sass/app.scss 2:14-253
When I compile assets with "npm run dev" there is no warnings after process.
Anyone have idea what's causing this behavior ?
app.scss content:
#use 'sass:math';
#use 'sass:list';
#import "compile/bootstrap";
#import "compile/bootstrap_limitless";
#import "compile/layout";
#import "compile/components";
#import "compile/colors";
#import "datatables";
#import "forms";
#import "daterangepicker";

Answer 1

I finally found the solution. SVGO package from Cssnano was the problem.
To fix this just add to mix.options (in webpack.mix.js file) following lines:
mix.options({
cssNano: {
svgo: false
}
});
That's all.