Angular error on build

Hi, I’ve installed the private npm package of my organisation which works like angular material, and I’ve imported the css of the same in styles.scss. When I run npm run build, sometimes this error occurs and sometimes it doesn’t. Anybody knows why and what’s the fix?

./node_modules/…………./core-ui-core.css – Error: Module Error (from ./node_modules/postcss-loader/dist/cjs.js): E:\…….node_modules\……..\core-ui-core.css:17292:619: Can’t resolve ‘%23a’ in ….