electron-builder v5.24.0 (it doesn't happen in 5.16.0)
Target: windows

The built app fails during startup page loading due a corrupted dependency in the app.asar file.

Steps:

• create a new project with this package.json

{
  "name": "test",
  "version": "1.0.0",
  "description": "test",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "build": {
    "appId": "your.id",
    "category": "your.app.category.type",
    "icon": "icon.ico",
    "iconUrl": "https://github.com/favicon.ico"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "debug": "^2.2.0",
    "edge-cs": "^1.0.0"
  },
  "devDependencies": {
    "electron": ""^1.3.3",
    "electron-builder": "^5.24.0"
  }
}

• Add required files:
  • icon.ico (at least 256x256)
  • index.js (can be empty)
• Exec:

npm install
node_modules/electron-builder/out/build-cli.js
cd dist/win-unpacked/resources
asar extract app.asar app.asar.extracted

• Open app.asar.extracted/node_modules/debug/package.json
  This file and others in the same package are corrupted.

I think the problem may have something to do with having modules with "executable code":

node_modules\edge-cs is not packed into asar archive - contains executable code
node_modules\electron is not packed into asar archive - contains executable code