Node.js Debugger Not Connecting in Chrome (DevTools) via --inspect – Heap Snapshot Stuck on Loading

I'm running a Node.js application written in TypeScript. I use VS Code for debugging and run the app using ts-node, with source maps enabled.

I'm running the app with the --inspect flag and using VS Code's "attach" debug configuration. The debugger is listening on ws://localhost:9229. But:

• Chrome DevTools does not show any targets under chrome://inspect.
• Opening the raw URL (http://localhost:9229/json) gives a valid JSON response.
• Manually opening the DevTools with the devtools:// URL works, but:
  • Heap snapshot is stuck on loading and never completes.

My setup:

tsconfig.json:

{
  "compilerOptions": {
    "target": "es6",
    "module": "commonjs",
    "sourceMap": true,
    "outDir": "dist"
  }
}

package.json scripts:

"scripts": {
  "dev": "set NODE_ENV=DEV && concurrently \"npx tsc --watch\" \"nodemon --inspect --delay 5s -q dist/src/index.js\""
}

I'm using concurrently to run the TypeScript compiler and Nodemon in parallel. Terminal output when running the npm run dev:

[1] For more information, check the blog post at https://a.co/cUPnyil
[1] (Use `node --trace-warnings ...` to show where the warning was created)
[1] query: SELECT VERSION() AS `version`
[0]
// here as you can see the debugger is attached
[0] 11:35:08 pm - Found 0 errors. Watching for file changes.
[1] Debugger listening on ws://127.0.0.1:9229/c825031b-1285-49e7-bd94-a21d840c4137
[1] For help, see: https://nodejs.org/en/docs/inspector
[0]
[0] 11:35:08 pm - Found 0 errors. Watching for file changes.
[1] Debugger listening on ws://127.0.0.1:9229/c825031b-1285-49e7-bd94-a21d840c4137

VS Code launch.json

{
  "version": "0.2.0",
  "configurations": [
    {
      "type": "node",
      "request": "attach",
      "name": "Debug cluster",
      "port": 9229,
      "skipFiles": [
        "<node_internals>/**",
        "${workspaceFolder}/node_modules/**"
      ],
      "sourceMaps": true,
      "outFiles": ["${workspaceFolder}/dist/**/*.js"]
    }
  ]
}

Output of http://localhost:9229/json:

[
  {
    "description": "node.js instance",
    "devtoolsFrontendUrl": "devtools://devtools/bundled/js_app.html?experiments=true&v8only=true&ws=localhost:9229/c825031b-1285-49e7-bd94-a21d840c4137",
    "devtoolsFrontendUrlCompat": "devtools://devtools/bundled/inspector.html?experiments=true&v8only=true&ws=localhost:9229/c825031b-1285-49e7-bd94-a21d840c4137",
    "title": "dist/src/index.js",
    "type": "node",
    "url": "file://<some>dist_src_index.js",
    "webSocketDebuggerUrl": "ws://localhost:9229/c825031b-1285-49e7-bd94-a21d840c4137"
  }
]

When I manually open the DevTools using the devtools:// URL above, it launches, but:

• Heap snapshot stays stuck on "Loading..."
• No memory profiling tools are usable.

Questions:

• Why is Chrome DevTools not listing my target under chrome://inspect even though --inspect is working?
• Why is the heap snapshot stuck on loading even when manually opening the DevTools?
• Am I missing some config or doing something wrong in the way I'm starting/debugging the app?

I've:

• Confirmed that source maps are correctly generated.
• Verified the .map files exist in dist/.
• Ensured no firewall or antivirus is blocking port 9229.
• Disabled all Chrome extensions.
• Tried a clean rebuild.
• Used Chrome and Edge (same issue).