Silent browser exceptions, script crash without notice

[a5af]

Using the npm run server default config. The ENV inside webpack.config reports as: server

If I add this statement that'll cause an exception in AppCtrl:
console.log(something_undefined);

Instead of seeing an exception notice in the console like:
Uncaught ReferenceError: something_undefined is not defined

nothing appears in the browser console. The script just stops loading at that point.

All the while, webpack reports:

Child html-webpack-plugin for "index.html":
chunk {0} index.html 712 bytes
webpack: bundle is now VALID.

Tried --bail option. But it makes no difference.
I'm wondering how no one else has posted about this. Is this a known issue?