Why doesn't the grunt-contrib-watch plugin grunt work?

Question

Grunt.js

I'm setting up a grant while doing css minification, js merging, js minification and image optimization.
If you run it manually, everything clearly works, but if I put it on watch , it somehow refuses to work, it just "looks" endlessly and that's it. Here is the Gruntfile.js code jsfiddle.net/e66z2uph Can
anyone tell me why changes are not being tracked? As far as I understand, everything should happen there instantly