Gulp task taking up 100% CPU time on OS X

I'm submitting a ... (check one with "x")

[ x] bug report => search github for a similar issue or PR before submitting
[ ] feature request
[ ] support request => Please do not submit support request here, instead see use [gitter](https://gitter.im/mgechev/angular2-seed) or [stackoverflow](https://stackoverflow.com/questions/tagged/angular2)

Current behavior
Do a fresh checkout. Run npm install followed by npm start. The application starts up in the browser as expected. Any change in source code will trigger a recompile as expected from watch but gulp will start taking up 100% CPU time and will not stop until the process is manually killed. BrowserSync becomes unresponsive.

Expected behavior
Gulp should not take up 100% CPU time. Seems to be an issue with watch?

Minimal reproduction of the problem with instructions
run npm start, wait until the demo is opened in the browser, then do any change in source to trigger a recompile.

What is the motivation / use case for changing the behavior?
Unable to use the seed for development on a Mac as it hogs the CPU.

Please tell us about your environment:

• Mac OS High Sierra
• npm 6.4.1
• nodejs v11.0.0

• Angular Seed Version: aaaaf75

• Node: node --version = v11.0.0

Reproduce the problem with npm install followed by npm start, then change source code and observe the watch rebuild, CPU usage, and BrowserSync. Trace the Gulp watch task and its interaction with the Angular seed build; done means a source change recompiles without sustained 100% CPU and BrowserSync remains responsive on the reported macOS environment.