🐞 Bug report

Command (mark with an x)

• [x ] build
• [x ] serve

Is this a regression?

Yes, the previous version in which this bug was not present was: 12.0.0-rc.1

Description

After upgrading my app to Angular CLI V 12, when I try to compile my Angular app it throws below error:

mixins.scss:7:10: Unknown word
You tried to parse SCSS with the standard CSS parser; try again with the postcss-scss parser

site.scss:84:1: Unknown word
You tried to parse SCSS with the standard CSS parser; try again with the postcss-scss parser

🔬 Minimal Reproduction

Upgrade any Angular app to V 12, and I believe it should have same behavior, since the only change I made in my project it upgrade to V12.

Below is my angular.json:

{
  "$schema": "./node_modules/@angular-devkit/core/src/workspace/workspace-schema.json",
  "version": 1,
  "newProjectRoot": "projects",
  "projects": {
    "Mustakbil": {
      "root": "",
      "sourceRoot": "src",
      "projectType": "application",
      "architect": {
        "build": {
          "builder": "ngx-build-plus:browser",
          "options": {
            "outputPath": "dist",
            "index": "src/index.html",
            "main": "src/main.ts",
            "tsConfig": "src/tsconfig.app.json",
            "progress": true,
            "aot": true,
            "polyfills": "src/polyfills.ts",
            "assets": [
              "src/assets",
              "src/manifest.json",
              "src/firebase-messaging-sw.js"
            ],
            "styles": [
              "src/assets/styles/site.scss"
            ],
            "scripts": []
          },
          "configurations": {
            "production": {
              "optimization": {
                "scripts": true,
                "styles": {
                  "minify": true,
                  "inlineCritical": false
                },
                "fonts": true
              },
              "outputHashing": "all",
              "sourceMap": false,
              "extractCss": true,
              "namedChunks": false,
              "aot": true,
              "extractLicenses": true,
              "vendorChunk": false,
              "buildOptimizer": true,
              "fileReplacements": [
                {
                  "replace": "src/environments/environment.ts",
                  "with": "src/environments/environment.prod.ts"
                }
              ],
              "serviceWorker": true
            }
          }
        },
        "serve": {
          "builder": "ngx-build-plus:dev-server",
          "options": {
            "browserTarget": "Mustakbil:build"
          },
          "configurations": {
            "production": {
              "browserTarget": "Mustakbil:build:production"
            }
          }
        },
        "extract-i18n": {
          "builder": "@angular-devkit/build-angular:extract-i18n",
          "options": {
            "browserTarget": "Mustakbil:build"
          }
        },
        "test": {
          "builder": "ngx-build-plus:karma",
          "options": {
            "main": "src/test.ts",
            "karmaConfig": "./karma.conf.js",
            "polyfills": "src/polyfills.ts",
            "tsConfig": "src/tsconfig.spec.json",
            "scripts": [],
            "styles": [
            ],
            "assets": [
              "src/assets",
              "src/manifest.json"
            ]
          }
        },
        "lint": {
          "builder": "@angular-devkit/build-angular:tslint",
          "options": {
            "tsConfig": [
              "src/tsconfig.app.json",
              "src/tsconfig.spec.json"
            ],
            "exclude": [
              "**/node_modules/**"
            ]
          }
        },
        "server": {
          "builder": "@angular-devkit/build-angular:server",
          "options": {
            "outputPath": "dist-server",
            "main": "src/main.server.ts",
            "tsConfig": "src/tsconfig.server.json",
            "sourceMap": true,
            "optimization": false
          },
          "configurations": {
            "production": {
              "optimization": true,
              "outputHashing": "media",
              "sourceMap": false,
              "namedChunks": false,
              "extractLicenses": true,
              "bundleDependencies": true,
              "fileReplacements": [
                {
                  "replace": "src/environments/environment.ts",
                  "with": "src/environments/environment.prod.ts"
                }
              ]
            }
          }
        },
        "prerender": {
          "builder": "@nguniversal/builders:prerender",
          "options": {
            "browserTarget": "Mustakbil:build:production",
            "serverTarget": "Mustakbil:server:production",
            "routes": [
              "/"
            ]
          },
          "configurations": {
            "production": {}
          }
        }
      }
    }
  },
  "defaultProject": "Mustakbil",
  "schematics": {
    "@schematics/angular:component": {
      "prefix": "app",
      "styleext": "scss"
    },
    "@schematics/angular:directive": {
      "prefix": "app"
    }
  }
}

🔥 Exception or Error

\assets\styles\mixins.scss:7:10: Unknown word
You tried to parse SCSS with the standard CSS parser; try again with the postcss-scss parser

\assets\styles\site.scss:84:1: Unknown word
You tried to parse SCSS with the standard CSS parser; try again with the postcss-scss parser

🌍 Your Environment

Angular CLI: 12.0.0
Node: 14.16.0
Package Manager: npm 6.14.11
OS: win32 x64

Angular: 12.0.0
... animations, cdk, cli, common, compiler, compiler-cli, core
... forms, google-maps, language-service, material
... platform-browser, platform-browser-dynamic, platform-server
... pwa, router, service-worker

Package                          Version
----------------------------------------------------------
@angular-devkit/architect        0.1200.0
@angular-devkit/build-angular    12.0.0
@angular-devkit/core             12.0.0
@angular-devkit/schematics       12.0.0
@angular/fire                    6.1.4
@nguniversal/aspnetcore-engine   12.0.0
@nguniversal/builders            12.0.0
@nguniversal/common              12.0.0
@schematics/angular              12.0.0
rxjs                             6.6.7
typescript                       4.2.3