I don't know whether this is the expected behaviour or not, however i just report this in case someone face the same problem..

in my package.json

  "jest": {
    "collectCoverageFrom": [
      "src/components/**/*.{js,jsx}"
    ]
  }

after apply react-app-rewired, the collectCoverageFrom become [ 'src/components/**/*.{js,jsx}', 'src/**/*.{js,jsx,mjs}' ], which is not the default behaviour of react-scripts, as it won't include the jest default 'src/**/*.{js,jsx,mjs}' .